Defer render_widget draw until host window is available

In accelerated compositing mode we can't start rendering until the
native window (HWND/gtk widget) are created on Windows and GTK without
aura. For most render_widgets the code today is racy, but for
window.open() and similar creation paths this is a race that we pretty
much always lose. This defers the first DoDeferredUpdate on a render_widget
until its host_window_ is available.

Also defers querying for GL_CHROMIUM_supports_swapbuffers_callback
extension until the first draw, since the context isn't ready until the
host window is available.

BUG=106815
TEST=start with --force-compositing-mode and --show-fps-counter, load up
a page that uses window.open() to open a popup, and confirm that the
popup is in compositing mode


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=119977

Review URL: http://codereview.chromium.org/9225050

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@120111 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 33 insertions, 9 deletions

diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index c8eb610..69bfb28 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -397,6 +397,8 @@ RenderViewImpl::RenderViewImpl(
       cached_is_main_frame_pinned_to_right_(false),
       cached_has_main_frame_horizontal_scrollbar_(false),
       cached_has_main_frame_vertical_scrollbar_(false),
+      context_has_swapbuffers_complete_callback_(false),
+      queried_for_swapbuffers_complete_callback_(false),
       ALLOW_THIS_IN_INITIALIZER_LIST(cookie_jar_(this)),
       geolocation_dispatcher_(NULL),
       speech_input_dispatcher_(NULL),
@@ -4495,12 +4497,21 @@ bool RenderViewImpl::SupportsAsynchronousSwapBuffers() {
   if (WebWidgetHandlesCompositorScheduling())
     return false;
 
+  if (queried_for_swapbuffers_complete_callback_)
+    return context_has_swapbuffers_complete_callback_;
+
+  queried_for_swapbuffers_complete_callback_ = true;
+
   WebKit::WebGraphicsContext3D* context = webview()->graphicsContext3D();
-  if (!context)
-    return false;
-  std::string extensions(context->getRequestableExtensionsCHROMIUM().utf8());
-  return extensions.find("GL_CHROMIUM_swapbuffers_complete_callback") !=
-      std::string::npos;
+  if (context) {
+    context->makeContextCurrent();
+    std::string extensions(context->getRequestableExtensionsCHROMIUM().utf8());
+    context_has_swapbuffers_complete_callback_ =
+        extensions.find("GL_CHROMIUM_swapbuffers_complete_callback")
+            != std::string::npos;
+  }
+
+  return context_has_swapbuffers_complete_callback_;
 }
 
 void RenderViewImpl::OnSetFocus(bool enable) {
diff --git a/content/renderer/render_view_impl.h b/content/renderer/render_view_impl.h
index b892a80..083ab85 100644
--- a/content/renderer/render_view_impl.h
+++ b/content/renderer/render_view_impl.h
@@ -1135,6 +1135,13 @@ class RenderViewImpl : public RenderWidget,
   std::set<gfx::PluginWindowHandle> fake_plugin_window_handles_;
 #endif
 
+  // When this view is composited, the context used for compositing may or may
+  // not support the GL_CHROMIUM_swapbuffers_complete_callback extension. Since
+  // querying for the existence of this extension is expensive we cache the
+  // result. These are used to implement SupportsAsynchronousSwapBuffers().
+  bool context_has_swapbuffers_complete_callback_;
+  bool queried_for_swapbuffers_complete_callback_;
+
   // Helper objects ------------------------------------------------------------
 
   RendererWebCookieJarImpl cookie_jar_;
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 3df2a99..6b16fa7 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -175,6 +175,8 @@ void RenderWidget::CompleteInit(gfx::NativeViewId parent_hwnd) {
 
   host_window_ = parent_hwnd;
 
+  DoDeferredUpdate();
+
   Send(new ViewHostMsg_RenderViewReady(routing_id_));
 }
 
@@ -737,6 +739,11 @@ void RenderWidget::DoDeferredUpdate() {
 
   if (!webwidget_)
     return;
+
+  if (!host_window_) {
+    TRACE_EVENT0("renderer", "EarlyOut_NoHostWindow");
+    return;
+  }
   if (update_reply_pending_) {
     TRACE_EVENT0("renderer", "EarlyOut_UpdateReplyPending");
     return;
@@ -755,6 +762,9 @@ void RenderWidget::DoDeferredUpdate() {
     return;
   }
 
+  if (is_accelerated_compositing_active_)
+    using_asynchronous_swapbuffers_ = SupportsAsynchronousSwapBuffers();
+
   // Tracking of frame rate jitter
   base::TimeTicks frame_begin_ticks = base::TimeTicks::Now();
   AnimateIfNeeded();
@@ -1010,10 +1020,6 @@ void RenderWidget::didActivateCompositor(int compositor_identifier) {
   is_accelerated_compositing_active_ = true;
   Send(new ViewHostMsg_DidActivateAcceleratedCompositing(
       routing_id_, is_accelerated_compositing_active_));
-
-  // Note: asynchronous swapbuffer support currently only matters if
-  // compositing scheduling happens on the RenderWidget.
-  using_asynchronous_swapbuffers_ = SupportsAsynchronousSwapBuffers();
 }
 
 void RenderWidget::didDeactivateCompositor() {