Revert 251918 "Do not send a frame swap ack from the browser unt..."

trunk/src/content/browser/renderer_host/compositing_iosurface_layer_mac.mm

Index: trunk/src/content/browser/renderer_host/compositing_iosurface_layer_mac.mm
===================================================================
--- trunk/src/content/browser/renderer_host/compositing_iosurface_layer_mac.mm	(revision 252030)
+++ trunk/src/content/browser/renderer_host/compositing_iosurface_layer_mac.mm	(working copy)
@@ -16,14 +16,6 @@
 #include "ui/gfx/size_conversions.h"
 #include "ui/gl/gpu_switching_manager.h"
 
-@interface CompositingIOSurfaceLayer()
-
-// Private method to wait for a frame of the right size if we're in an active
-// resize. This may potentially dispatch select messages from the run loop.
-- (void)waitForResizedFrameInContext:(CGLContextObj)glContext;
-
-@end
-
 @implementation CompositingIOSurfaceLayer
 
 @synthesize context = context_;
@@ -74,41 +66,6 @@
     [self setNeedsDisplay];
 }
 
-- (void)waitForResizedFrameInContext:(CGLContextObj)glContext {
-  // Cache a copy of renderWidgetHostView_ because it may be reset if
-  // a software frame is received in GetBackingStore.
-  content::RenderWidgetHostViewMac* cached_view = renderWidgetHostView_;
-  if (!cached_view->render_widget_host_ ||
-      cached_view->render_widget_host_->is_hidden()) {
-    return;
-  }
-
-  // Note that GetBackingStore can potentially spawn a nested run loop, which
-  // may change the current GL context, or, because the GL contexts are
-  // shared, may change the currently-bound FBO. Ensure that, when the run
-  // loop returns, the original GL context remain current, and the original
-  // FBO remain bound.
-  // TODO(ccameron): This is far too fragile a mechanism to rely on. Find
-  // a way to avoid doing this.
-  GLuint previous_framebuffer = 0;
-  glGetIntegerv(GL_FRAMEBUFFER_BINDING,
-                reinterpret_cast<GLint*>(&previous_framebuffer));
-  {
-    // If a resize is in progress then GetBackingStore request a frame of the
-    // current window size and block until a frame of the right size comes in.
-    // This makes the window content not lag behind the resize (at the cost of
-    // blocking on the browser's main thread).
-    gfx::ScopedCGLSetCurrentContext scoped_set_current_context(NULL);
-    cached_view->about_to_validate_and_paint_ = true;
-    (void)cached_view->render_widget_host_->GetBackingStore(true);
-    cached_view->about_to_validate_and_paint_ = false;
-  }
-  CHECK_EQ(CGLGetCurrentContext(), glContext)
-      << "original GL context failed to re-bind after nested run loop, "
-      << "browser crash is imminent.";
-  glBindFramebuffer(GL_FRAMEBUFFER, previous_framebuffer);
-}
-
 // The remaining methods implement the CAOpenGLLayer interface.
 
 - (CGLPixelFormatObj)copyCGLPixelFormatForDisplayMask:(uint32_t)mask {
@@ -150,12 +107,36 @@
     return;
   }
 
-  // Acknowledge the frame before we potentially wait for a frame of the right
-  // size.
-  renderWidgetHostView_->SendPendingSwapAck();
+  // Cache a copy of renderWidgetHostView_ because it may be reset if
+  // a software frame is received in GetBackingStore.
+  content::RenderWidgetHostViewMac* cached_view = renderWidgetHostView_;
 
-  // Wait for a frame of the right size to come in, if needed.
-  [self waitForResizedFrameInContext:glContext];
+  // If a resize is in progress then GetBackingStore request a frame of the
+  // current window size and block until a frame of the right size comes in.
+  // This makes the window content not lag behind the resize (at the cost of
+  // blocking on the browser's main thread).
+  if (cached_view->render_widget_host_) {
+    // Note that GetBackingStore can potentially spawn a nested run loop, which
+    // may change the current GL context, or, because the GL contexts are
+    // shared, may change the currently-bound FBO. Ensure that, when the run
+    // loop returns, the original GL context remain current, and the original
+    // FBO remain bound.
+    // TODO(ccameron): This is far too fragile a mechanism to rely on. Find
+    // a way to avoid doing this.
+    GLuint previous_framebuffer = 0;
+    glGetIntegerv(GL_FRAMEBUFFER_BINDING,
+                  reinterpret_cast<GLint*>(&previous_framebuffer));
+    {
+      gfx::ScopedCGLSetCurrentContext scoped_set_current_context(NULL);
+      cached_view->about_to_validate_and_paint_ = true;
+      (void)cached_view->render_widget_host_->GetBackingStore(true);
+      cached_view->about_to_validate_and_paint_ = false;
+    }
+    CHECK_EQ(CGLGetCurrentContext(), glContext)
+        << "original GL context failed to re-bind after nested run loop, "
+        << "browser crash is imminent.";
+    glBindFramebuffer(GL_FRAMEBUFFER, previous_framebuffer);
+  }
 
   // If a transition to software mode has occurred, this layer should be
   // removed from the heirarchy now, so don't draw anything.