Sets a transparent background for out-of-process subframes.

third_party/WebKit/Source/web/WebFrameWidgetImpl.h

Index: third_party/WebKit/Source/web/WebFrameWidgetImpl.h
diff --git a/third_party/WebKit/Source/web/WebFrameWidgetImpl.h b/third_party/WebKit/Source/web/WebFrameWidgetImpl.h
index 686f1a499409df5ef02d3018492bf076a94753bb..a9629b31568422645e69f5e4eaf662b0d3c16bd6 100644
--- a/third_party/WebKit/Source/web/WebFrameWidgetImpl.h
+++ b/third_party/WebKit/Source/web/WebFrameWidgetImpl.h
@@ -115,6 +115,13 @@ public:
     void willCloseLayerTreeView() override;
     void didChangeWindowResizerRect() override;
 
+    // WebFrameWidget implementation.
+    void setVisibilityState(WebPageVisibilityState, bool) override;
+    bool isTransparent() const override;
+    void setIsTransparent(bool) override;
+    void setBaseBackgroundColor(WebColor) override;
+    void scheduleAnimation() override;
+
     WebWidgetClient* client() const { return m_client; }
 
     Frame* focusedCoreFrame() const;
@@ -122,15 +129,11 @@ public:
     // Returns the currently focused Element or null if no element has focus.
     Element* focusedElement() const;
 
-    void scheduleAnimation() override;
-
     PaintLayerCompositor* compositor() const;
     void setRootGraphicsLayer(GraphicsLayer*);
     void attachCompositorAnimationTimeline(CompositorAnimationTimeline*);
     void detachCompositorAnimationTimeline(CompositorAnimationTimeline*);
 
-    void setVisibilityState(WebPageVisibilityState, bool) override;
-
     // Exposed for the purpose of overriding device metrics.
     void sendResizeEventAndRepaint();
 
@@ -153,6 +156,8 @@ public:
         ScrollDirection*,
         ScrollGranularity*);
 
+    Color baseBackgroundColor() const { return m_baseBackgroundColor; }
+
     DECLARE_TRACE();
 
 private:
@@ -182,8 +187,6 @@ private:
     void updateLayerTreeBackgroundColor();
     void updateLayerTreeDeviceScaleFactor();
 
-    bool isTransparent() const;
-
     // PageWidgetEventHandler functions
     void handleMouseLeave(LocalFrame&, const WebMouseEvent&) override;
     void handleMouseDown(LocalFrame&, const WebMouseEvent&) override;
@@ -217,8 +220,13 @@ private:
 
     bool m_ignoreInputEvents;
 
+    // Whether the WebFrameWidget is rendering transparently.
+    bool m_isTransparent;
+
     static const WebInputEvent* m_currentInputEvent;
 
+    WebColor m_baseBackgroundColor;
+
 #if ENABLE(OILPAN)
     SelfKeepAlive<WebFrameWidgetImpl> m_selfKeepAlive;
 #endif