Make OffscreenCanvas resizable

third_party/WebKit/Source/platform/graphics/CanvasSurfaceLayerBridge.cpp

Index: third_party/WebKit/Source/platform/graphics/CanvasSurfaceLayerBridge.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/CanvasSurfaceLayerBridge.cpp b/third_party/WebKit/Source/platform/graphics/CanvasSurfaceLayerBridge.cpp
index 0c58ec665a9bc86ec78c5b9e086ec11525119270..afeead46903af7074eceb5bfc6e7e31e10685c66 100644
--- a/third_party/WebKit/Source/platform/graphics/CanvasSurfaceLayerBridge.cpp
+++ b/third_party/WebKit/Source/platform/graphics/CanvasSurfaceLayerBridge.cpp
@@ -88,14 +88,13 @@ void CanvasSurfaceLayerBridge::OnSurfaceCreated(const cc::SurfaceId& surfaceId,
                                                 int32_t width,
                                                 int32_t height,
                                                 float deviceScaleFactor) {
-  if (!m_currentSurfaceId.is_valid() && surfaceId.is_valid()) {
+  if (surfaceId.is_valid() && !m_currentSurfaceId.is_valid()) {
     m_currentSurfaceId = surfaceId;
     GraphicsLayer::unregisterContentsLayer(m_webLayer.get());
     m_webLayer->removeFromParent();
 
     scoped_refptr<cc::SurfaceLayer> surfaceLayer =
         cc::SurfaceLayer::Create(m_refFactory);
-    // TODO(xlai): Update this on resize.
     cc::SurfaceInfo info(surfaceId, deviceScaleFactor,
                          gfx::Size(width, height));
     surfaceLayer->SetSurfaceInfo(
@@ -108,6 +107,15 @@ void CanvasSurfaceLayerBridge::OnSurfaceCreated(const cc::SurfaceId& surfaceId,
     GraphicsLayer::registerContentsLayer(m_webLayer.get());
 
     m_observer->OnWebLayerReplaced();
+  } else if (m_currentSurfaceId != surfaceId) {
+    m_currentSurfaceId = surfaceId;
+    cc::SurfaceInfo info(m_currentSurfaceId, deviceScaleFactor,
+                         gfx::Size(width, height));
+    cc::SurfaceLayer* surfaceLayer =
+        static_cast<cc::SurfaceLayer*>(m_CCLayer.get());
+    surfaceLayer->SetSurfaceInfo(info, true);

[Fady Samuel, 2016/12/19 20:12:40]

I think you also need to update the layer bounds?
https://cs.chromium.org/chromium/src/content/renderer/child_frame_compositing...

[xlai (Olivia), 2016/12/19 22:30:15]

Although there is no visible effect seen at the moment, I agree that 
it is more correct to update layer bounds. 

+
+    m_observer->OnWebLayerReplaced();
   }
 }