Pass values in CSS pixel scale to ContentViewCore::UpdateFrameInfo

ContentViewCore::UpdateFrameInfo() must receive positions and sizes in CSS pixel
except top_shown_pix. When --use-zoom-for-dsf is enabled, those values given to
ContentViewCore::UpdateFrameInfo() are in physical pixel. It results in test
failures of ContentViewScrollingTest#testOverScroll and
ContentViewScrollingTest#testScrollTo. This CL scales down those values given to
ContentViewCore::UpdateFrameInfo() by the device scale factor.

TEST=run_content_shell_test_apk -f ContentViewScrollingTest#testOverScroll
(and ContentViewScrollingTest#testScrollTo) on NEXUS 5X

Bug: 737777
Change-Id: I95be3ed63d569ec9d620fa431c0d6bfa932410ba
Reviewed-on: https://chromium-review.googlesource.com/888183
Commit-Queue: Jaebaek Seo <jaebaek@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533129}

content/browser/renderer_host/render_widget_host_view_android.cc

@@ -1461,12 +1461,23 @@ void RenderWidgetHostViewAndroid::OnFrameMetadataUpdated(
   gesture_provider_.SetDoubleTapSupportForPageEnabled(!is_mobile_optimized);
 
   float dip_scale = view_.GetDipScale();
+  gfx::SizeF root_layer_size_dip = frame_metadata.root_layer_size;
+  gfx::SizeF scrollable_viewport_size_dip =
+      frame_metadata.scrollable_viewport_size;
+  gfx::Vector2dF root_scroll_offset_dip = frame_metadata.root_scroll_offset;
+  if (IsUseZoomForDSFEnabled()) {
+    float pix_to_dip = 1 / dip_scale;
+    root_layer_size_dip.Scale(pix_to_dip);
+    scrollable_viewport_size_dip.Scale(pix_to_dip);
+    root_scroll_offset_dip.Scale(pix_to_dip);
+  }
+
   float to_pix = IsUseZoomForDSFEnabled() ? 1.f : dip_scale;
   float top_controls_pix = frame_metadata.top_controls_height * to_pix;
-  // |top_content_offset| is its CSS pixels * DSF if --use-zoom-for-dsf is
-  // enabled. Otherwise, it is in CSS pixels.
+  // |top_content_offset| is in physical pixels if --use-zoom-for-dsf is
+  // enabled. Otherwise, it is in DIPs.
   // Note that the height of browser control is not affected by page scale
-  // factor. Thus, |top_content_offset| in CSS pixels is also in DIP pixels.
+  // factor. Thus, |top_content_offset| in CSS pixels is also in DIPs.
   float top_content_offset = frame_metadata.top_controls_height *
                              frame_metadata.top_controls_shown_ratio;
   float top_shown_pix = top_content_offset * to_pix;
@@ -1494,7 +1505,7 @@ void RenderWidgetHostViewAndroid::OnFrameMetadataUpdated(
         frame_metadata.page_scale_factor);
 
     // Set parameters for adaptive handle orientation.
-    gfx::SizeF viewport_size(frame_metadata.scrollable_viewport_size);
+    gfx::SizeF viewport_size(scrollable_viewport_size_dip);
     viewport_size.Scale(frame_metadata.page_scale_factor);
     gfx::RectF viewport_rect(0.0f, frame_metadata.top_controls_height *
                                        frame_metadata.top_controls_shown_ratio,
@@ -1506,11 +1517,10 @@ void RenderWidgetHostViewAndroid::OnFrameMetadataUpdated(
                                        : frame_metadata.root_background_color);
 
   // ViewAndroid::content_offset() must be in CSS scale
-  float top_content_offset_css = IsUseZoomForDSFEnabled()
+  float top_content_offset_dip = IsUseZoomForDSFEnabled()
                                      ? top_content_offset / dip_scale
                                      : top_content_offset;
-  view_.UpdateFrameInfo(
-      {frame_metadata.scrollable_viewport_size, top_content_offset});
+  view_.UpdateFrameInfo({scrollable_viewport_size_dip, top_content_offset});
 
   bool top_changed = !FloatEquals(top_shown_pix, prev_top_shown_pix_);
   if (top_changed) {
@@ -1535,11 +1545,11 @@ void RenderWidgetHostViewAndroid::OnFrameMetadataUpdated(
 
   // All offsets and sizes except |top_shown_pix| are in CSS pixels.
   content_view_core_->UpdateFrameInfo(
-      frame_metadata.root_scroll_offset, frame_metadata.page_scale_factor,
+      root_scroll_offset_dip, frame_metadata.page_scale_factor,
       frame_metadata.min_page_scale_factor,
-      frame_metadata.max_page_scale_factor, frame_metadata.root_layer_size,
-      frame_metadata.scrollable_viewport_size, top_content_offset_css,
-      top_shown_pix, top_changed, is_mobile_optimized);
+      frame_metadata.max_page_scale_factor, root_layer_size_dip,
+      scrollable_viewport_size_dip, top_content_offset_dip, top_shown_pix,
+      top_changed, is_mobile_optimized);
 
   EvictFrameIfNecessary();
 }