Simplify the BackingStore handling.

This patch removes the black borders around the widget when resizing.

- No need to resize the BackingStore direcly, RenderWidgetHostImpl::WasResized
  takes care of allocating a new one with the correct size.
- Get the backing store just before painting instead of pushing it when
  scheduling an update. Getting the backing store has side effects that
  assumes it is done that way.
- Remove the about_to_validate_and_paint_ check as all our painting updates
  are scheduled back to the event loop and that we are now only fetching
  the BackingStore at this point.

4 files changed, 18 insertions, 38 deletions

diff --git a/lib/render_widget_host_view_qt_delegate_quick.cpp b/lib/render_widget_host_view_qt_delegate_quick.cpp
index 754e68239..13e4ef29f 100644
--- a/lib/render_widget_host_view_qt_delegate_quick.cpp
+++ b/lib/render_widget_host_view_qt_delegate_quick.cpp
@@ -2,6 +2,9 @@
 
 #include "shared/backing_store_qt.h"
 #include "shared/render_widget_host_view_qt.h"
+
+#include "content/browser/renderer_host/render_view_host_impl.h"
+
 #include <QQuickWindow>
 #include <QWindow>
 
@@ -42,6 +45,7 @@ QWindow* RenderWidgetHostViewQtDelegateQuick::window() const
 
 void RenderWidgetHostViewQtDelegateQuick::update(const QRect& rect)
 {
+    polish();
     QQuickPaintedItem::update(rect);
 }
 
@@ -53,29 +57,19 @@ void RenderWidgetHostViewQtDelegateQuick::paint(QPainter *painter)
     m_backingStore->paintToTarget(painter, boundingRect());
 }
 
-void RenderWidgetHostViewQtDelegateQuick::setBackingStore(BackingStoreQt* backingStore)
-{
-    m_backingStore = backingStore;
-    if (m_backingStore)
-        m_backingStore->resize(QSize(width(), height()));
-}
-
-QSGNode * RenderWidgetHostViewQtDelegateQuick::updatePaintNode(QSGNode * oldNode, UpdatePaintNodeData * data)
+void RenderWidgetHostViewQtDelegateQuick::updatePolish()
 {
-    return QQuickPaintedItem::updatePaintNode(oldNode, data);
+    // paint will be called from the scene graph thread and this doesn't play well
+    // with chromium's use of TLS while getting the backing store.
+    // updatePolish() should be called from the GUI thread right before the rendering thread starts.
+    m_backingStore = m_view->GetBackingStore();
 }
 
 void RenderWidgetHostViewQtDelegateQuick::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
 {
     QQuickPaintedItem::geometryChanged(newGeometry, oldGeometry);
 
-    resizeBackingStore();
-}
-
-void RenderWidgetHostViewQtDelegateQuick::resizeBackingStore()
-{
-    if (m_backingStore)
-        m_backingStore->resize(QSize(width(), height()));
+    m_view->GetRenderWidgetHost()->WasResized();
 }
 
 void RenderWidgetHostViewQtDelegateQuick::focusInEvent(QFocusEvent *event)
diff --git a/lib/render_widget_host_view_qt_delegate_quick.h b/lib/render_widget_host_view_qt_delegate_quick.h
index 20725c621..20bd263f8 100644
--- a/lib/render_widget_host_view_qt_delegate_quick.h
+++ b/lib/render_widget_host_view_qt_delegate_quick.h
@@ -23,7 +23,6 @@ class RenderWidgetHostViewQtDelegateQuick : public QQuickPaintedItem, public Ren
 public:
     RenderWidgetHostViewQtDelegateQuick(content::RenderWidgetHostViewQt* view, QQuickItem *parent = 0);
 
-    virtual void setBackingStore(BackingStoreQt* backingStore);
     virtual QRectF screenRect() const;
     virtual void show();
     virtual void hide();
@@ -43,11 +42,8 @@ public:
     void keyReleaseEvent(QKeyEvent*);
     void wheelEvent(QWheelEvent*);
 
-protected Q_SLOTS:
-    void resizeBackingStore();
-
 protected:
-    QSGNode* updatePaintNode(QSGNode * oldNode, UpdatePaintNodeData * data);
+    void updatePolish();
     void geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry);
 
 private:
diff --git a/lib/render_widget_host_view_qt_delegate_widget.cpp b/lib/render_widget_host_view_qt_delegate_widget.cpp
index 8be1d308f..9a659069f 100644
--- a/lib/render_widget_host_view_qt_delegate_widget.cpp
+++ b/lib/render_widget_host_view_qt_delegate_widget.cpp
@@ -3,13 +3,14 @@
 #include "shared/backing_store_qt.h"
 #include "shared/render_widget_host_view_qt.h"
 
+#include "content/browser/renderer_host/render_view_host_impl.h"
+
 #include <QResizeEvent>
 #include <QPaintEvent>
 
 RenderWidgetHostViewQtDelegateWidget::RenderWidgetHostViewQtDelegateWidget(content::RenderWidgetHostViewQt* view, QWidget *parent)
     : QWidget(parent)
     , m_painter(0)
-    , m_backingStore(0)
     , m_view(view)
 {
     setFocusPolicy(Qt::ClickFocus);
@@ -47,19 +48,12 @@ void RenderWidgetHostViewQtDelegateWidget::update(const QRect& rect)
     QWidget::update(rect);
 }
 
-void RenderWidgetHostViewQtDelegateWidget::setBackingStore(BackingStoreQt* backingStore)
-{
-    m_backingStore = backingStore;
-    if (m_backingStore)
-        m_backingStore->resize(size());
-}
-
 void RenderWidgetHostViewQtDelegateWidget::paintEvent(QPaintEvent * event)
 {
-    if (!m_backingStore)
-        return;
-    QPainter painter(this);
-    m_backingStore->paintToTarget(&painter, event->rect());
+    if (BackingStoreQt *backingStore = m_view->GetBackingStore()) {
+        QPainter painter(this);
+        backingStore->paintToTarget(&painter, event->rect());
+    }
 }
 
 QPainter* RenderWidgetHostViewQtDelegateWidget::painter()
@@ -71,9 +65,7 @@ QPainter* RenderWidgetHostViewQtDelegateWidget::painter()
 
 void RenderWidgetHostViewQtDelegateWidget::resizeEvent(QResizeEvent *resizeEvent)
 {
-    if (m_backingStore)
-        m_backingStore->resize(resizeEvent->size());
-    QWidget::update();
+    m_view->GetRenderWidgetHost()->WasResized();
 }
 
 bool RenderWidgetHostViewQtDelegateWidget::event(QEvent *event)
diff --git a/lib/render_widget_host_view_qt_delegate_widget.h b/lib/render_widget_host_view_qt_delegate_widget.h
index 9087ba017..f6da4f484 100644
--- a/lib/render_widget_host_view_qt_delegate_widget.h
+++ b/lib/render_widget_host_view_qt_delegate_widget.h
@@ -17,7 +17,6 @@ class RenderWidgetHostViewQtDelegateWidget : public QWidget, public RenderWidget
 public:
     RenderWidgetHostViewQtDelegateWidget(content::RenderWidgetHostViewQt* view, QWidget *parent = 0);
 
-    virtual void setBackingStore(BackingStoreQt* backingStore);
     virtual QRectF screenRect() const;
     virtual void show();
     virtual void hide();
@@ -33,7 +32,6 @@ protected:
     void resizeEvent(QResizeEvent *resizeEvent);
 
 private:
-    BackingStoreQt* m_backingStore;
     QPainter* m_painter;
     content::RenderWidgetHostViewQt *m_view;
 };