Use contents size for android_webview layout.

android_webview/common/render_view_messages.h

Index: android_webview/common/render_view_messages.h
diff --git a/android_webview/common/render_view_messages.h b/android_webview/common/render_view_messages.h
index 96d17589c7120f1176e8afd0f41ab398f9ef2e62..33434072b356977207c03fb7cf030e2160d2db40 100644
--- a/android_webview/common/render_view_messages.h
+++ b/android_webview/common/render_view_messages.h
@@ -69,11 +69,14 @@ IPC_MESSAGE_ROUTED1(AwViewMsg_SetInitialPageScale,
 
 // Sets the base background color for this view.
 IPC_MESSAGE_ROUTED1(AwViewMsg_SetBackgroundColor,
-                    SkColor);
+                    SkColor)
 
 IPC_MESSAGE_CONTROL1(AwViewMsg_SetJsOnlineProperty,
                      bool /* network_up */)
 
+// Enables the sending of content size change notifications by the renderer.
+IPC_MESSAGE_ROUTED0(AwViewMsg_EnableContentsSizeNotifications)
+
 //-----------------------------------------------------------------------------
 // RenderView messages
 // These are messages sent from the renderer to the browser process.
@@ -90,3 +93,7 @@ IPC_MESSAGE_ROUTED1(AwViewHostMsg_UpdateHitTestData,
 // Sent whenever the page scale factor (as seen by RenderView) is changed.
 IPC_MESSAGE_ROUTED1(AwViewHostMsg_PageScaleFactorChanged,
                     float /* page_scale_factor */)
+
+// Sent whenever the contents size (as seen by RenderView) is changed.
+IPC_MESSAGE_ROUTED1(AwViewHostMsg_OnContentsSizeChanged,
+                    gfx::Size /* contents_size */)