Make new-style page scale work on Android.

- Fix CC's PinchZoomViewport and MaxScrollOffset logic to work in fixed
  layout mode.  Root layer max scroll offset is based on
  WebKit-perceived outer viewport and therefore should logically use
  layout_viewport_size_, whereas the inner one is the true user-visible
  viewport and therefore should use device_viewport_size_.

- Fix Android to send down viewport size in DIP when
  --enable-css-transform-pinch is not specified.  Default to
  non-CSS-transform mode when in impl-side painting.

- Make ContentSize() return bounds() instead of contentBounds() and
  rename to ScrollableSize for clarity.  This lets us avoid coordinate
  space conversions when computing max scroll offset.

BUG=152505
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/11958004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@177896 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 6 deletions

diff --git a/cc/pinch_zoom_viewport.cc b/cc/pinch_zoom_viewport.cc
index dab6c9c..3f3e3a1 100644
--- a/cc/pinch_zoom_viewport.cc
+++ b/cc/pinch_zoom_viewport.cc
@@ -50,16 +50,17 @@ bool PinchZoomViewport::SetPageScaleFactorAndLimits(
   return true;
 }
 
-gfx::RectF PinchZoomViewport::Bounds() const {
-  gfx::RectF bounds(gfx::PointF(), layout_viewport_size_);
-  bounds.Scale(1 / total_page_scale_factor());
-  bounds += zoomed_viewport_offset_;
-  return bounds;
+gfx::RectF PinchZoomViewport::ZoomedViewport() const {
+  gfx::SizeF layout_space_device_viewport_size = gfx::ScaleSize(
+      device_viewport_size_,
+      1 / (device_scale_factor_ * total_page_scale_factor()));
+  return gfx::RectF(gfx::PointAtOffsetFromOrigin(zoomed_viewport_offset_),
+                    layout_space_device_viewport_size);
 }
 
 gfx::Vector2dF PinchZoomViewport::ApplyScroll(const gfx::Vector2dF delta) {
   gfx::Vector2dF overflow;
-  gfx::RectF pinched_bounds = Bounds() + delta;
+  gfx::RectF pinched_bounds = ZoomedViewport() + delta;
 
   if (pinched_bounds.x() < 0) {
     overflow.set_x(pinched_bounds.x());