(not for review) Fix composited-to-non-composited corruption on Linux.

content/browser/renderer_host/render_widget_host_view_gtk.cc

Index: content/browser/renderer_host/render_widget_host_view_gtk.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_gtk.cc b/content/browser/renderer_host/render_widget_host_view_gtk.cc
index 1fe5d4c3e54070707a1b091f05efc165ce15b2f1..d8692d69500905ef663a5b5b23d257cb0dc0ac73 100644
--- a/content/browser/renderer_host/render_widget_host_view_gtk.cc
+++ b/content/browser/renderer_host/render_widget_host_view_gtk.cc
@@ -4,12 +4,6 @@
 
 #include "content/browser/renderer_host/render_widget_host_view_gtk.h"
 
-#include <cairo/cairo.h>
-#include <gdk/gdk.h>
-#include <gdk/gdkkeysyms.h>
-#include <gdk/gdkx.h>
-#include <gtk/gtk.h>
-
 #include <algorithm>
 #include <string>
 
@@ -25,6 +19,8 @@
 #include "base/time/time.h"
 #include "content/browser/accessibility/browser_accessibility_gtk.h"
 #include "content/browser/accessibility/browser_accessibility_manager_gtk.h"
+#include "content/browser/gpu/gpu_process_host.h"
+#include "content/browser/gpu/gpu_process_host_ui_shim.h"
 #include "content/browser/renderer_host/backing_store_gtk.h"
 #include "content/browser/renderer_host/gtk_im_context_wrapper.h"
 #include "content/browser/renderer_host/gtk_key_bindings_handler.h"
@@ -50,6 +46,12 @@
 #include "ui/gfx/text_elider.h"
 #include "webkit/common/cursors/webcursor_gtk_data.h"
 
+#include <cairo/cairo.h>
+#include <gdk/gdk.h>
+#include <gdk/gdkkeysyms.h>
+#include <gdk/gdkx.h>
+#include <gtk/gtk.h>
+
 using WebKit::WebMouseWheelEvent;
 using WebKit::WebScreenInfo;
 
@@ -554,6 +556,7 @@ RenderWidgetHostViewGtk::RenderWidgetHostViewGtk(RenderWidgetHost* widget_host)
       dragged_at_horizontal_edge_(0),
       dragged_at_vertical_edge_(0),
       compositing_surface_(gfx::kNullPluginWindow),
+      last_frame_was_composited_(false),
       last_mouse_down_(NULL) {
   host_->SetView(this);
   if (host_->is_hidden())
@@ -1067,6 +1070,17 @@ void RenderWidgetHostViewGtk::AcceleratedSurfaceBuffersSwapped(
   RenderWidgetHostImpl::AcknowledgeBufferPresent(
       params.route_id, gpu_host_id, ack_params);
   host_->FrameSwapped(params.latency_info);
+
+  if (!last_frame_was_composited_ &&
+      compositing_surface_ != gfx::kNullPluginWindow) {
+    GpuProcessHostUIShim* host = GpuProcessHostUIShim::GetOneInstance();
+    int32 surface_id = compositing_surface_;
+    if (host) {
+      bool compositing_active = true;
+      host->AcceleratedCompositingStateChange(surface_id, compositing_active);
+    }
+    last_frame_was_composited_ = true;
+  }
 }
 
 void RenderWidgetHostViewGtk::AcceleratedSurfacePostSubBuffer(
@@ -1158,6 +1172,7 @@ void RenderWidgetHostViewGtk::Paint(const gfx::Rect& damage_rect) {
   // call the compositor directly.
   RenderWidgetHostImpl* render_widget_host =
       RenderWidgetHostImpl::From(GetRenderWidgetHost());
+
   if (render_widget_host->is_accelerated_compositing_active()) {
     host_->ScheduleComposite();
     return;
@@ -1215,6 +1230,17 @@ void RenderWidgetHostViewGtk::Paint(const gfx::Rect& damage_rect) {
     if (whiteout_start_time_.is_null())
       whiteout_start_time_ = base::TimeTicks::Now();
   }
+
+  if (last_frame_was_composited_ &&
+    compositing_surface_ != gfx::kNullPluginWindow) {
+    GpuProcessHostUIShim* host = GpuProcessHostUIShim::GetOneInstance();
+    int32 surface_id = compositing_surface_;
+    if (host) {
+      bool compositing_active = false;
+      host->AcceleratedCompositingStateChange(surface_id, compositing_active);
+    }
+    last_frame_was_composited_ = false;
+  }
 }
 
 void RenderWidgetHostViewGtk::ShowCurrentCursor() {