Remove android webview rendering cruft

android_webview/browser/parent_compositor_draw_constraints.cc

Index: android_webview/browser/parent_compositor_draw_constraints.cc
diff --git a/android_webview/browser/parent_compositor_draw_constraints.cc b/android_webview/browser/parent_compositor_draw_constraints.cc
index e507d434e640bb05692527f0b4b47c3df9d316b0..e6b60d58a611e8fd6a9462b14f18a331e93df497 100644
--- a/android_webview/browser/parent_compositor_draw_constraints.cc
+++ b/android_webview/browser/parent_compositor_draw_constraints.cc
@@ -4,6 +4,8 @@
 
 #include "android_webview/browser/parent_compositor_draw_constraints.h"
 
+#include "android_webview/browser/child_frame.h"
+
 namespace android_webview {
 
 ParentCompositorDrawConstraints::ParentCompositorDrawConstraints()
@@ -17,13 +19,17 @@ ParentCompositorDrawConstraints::ParentCompositorDrawConstraints(
     : is_layer(is_layer), transform(transform), surface_rect(surface_rect) {
 }
 
-bool ParentCompositorDrawConstraints::Equals(
-    const ParentCompositorDrawConstraints& other) const {
-  if (is_layer != other.is_layer || transform != other.transform)
-    return false;
+bool ParentCompositorDrawConstraints::NeedUpdate(

[hush (inactive), 2015/03/18 22:29:27]

I'm kind of confused by the logic of NeedUpdate.
In the case of animating in and out of the screen, the last constraint before
going offscreen and the first constraint after going onscreen could be the same.
And in this case, the hardware renderer should force the draw constraints to
SRS.
But NeedUpdate will return false if the constraints are the same?

[boliu, 2015/03/18 22:34:07]

You are right.

To get the same effect, we need to pass the draw viewport here, and check if
it's empty here.. (or maybe just compare the size to surface_rect.size())

+    const ChildFrame& frame) const {
+  if (is_layer != frame.is_layer ||
+      transform != frame.transform_for_tile_priority) {
+    return true;
+  }
 
-  // Don't care about the surface size when neither is on a layer.
-  return !is_layer || surface_rect == other.surface_rect;
+  // Only care about surface size when we are not a layer and not in pre-raster

[hush (inactive), 2015/03/18 22:29:27]

I think the comment is "only care about surface size when we are on a layer and
not in pre-raster mode."

+  // is turned on.

[hush (inactive), 2015/03/18 22:29:27]

remove "is turned on"

+  return is_layer && !frame.offscreen_pre_raster &&
+         surface_rect != frame.viewport_for_tile_priority;
 }
 
 }  // namespace webview