Clobber frame_data->device_scale_factor to 1 on Android.

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 644343df3754e8b8d962c298eb860135033e7536..5691cd33932e5317897a477256fb9f297153b161 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -794,6 +794,13 @@ void RenderWidgetHostViewAndroid::SwapDelegatedFrame(
     last_output_surface_id_ = output_surface_id;
   }
 
+  // DelegatedRendererLayerImpl applies the inverse device_scale_factor of the
+  // renderer frame, assuming that the browser compositor will scale
+  // it back up to device scale.  But on Android we put our browser layers in
+  // physical pixels and set our browser CC device_scale_factor to 1, so this
+  // suppresses the transform.

[jamesr, 2014/06/12 23:00:04]

maybe include a link to the crbug about multiple monitor support on Android
since whoever ends up working on that bug is going to run into this?

[aelias_OOO_until_Jul13, 2014/06/13 00:17:46]

crbug archeology didn't turn up anything, but I linked newly filed bug
http://crbug.com/384134

[jamesr, 2014/06/13 00:27:53]

I was thinking of http://code.google.com/p/chromium/issues/detail?id=310763

[aelias_OOO_until_Jul13, 2014/06/13 00:36:07]

OK, linked.

+  frame_data->device_scale_factor = 1.0f;
+
   if (!has_content) {
     DestroyDelegatedContent();
   } else {
@@ -818,19 +825,6 @@ void RenderWidgetHostViewAndroid::SwapDelegatedFrame(
     layer_->SetContentsOpaque(true);
     layer_->SetBounds(content_size_in_layer_);
     layer_->SetNeedsDisplay();
-    // DelegatedRendererLayer scales the frame data from physical space to DIPs
-    // by inverting the frame's device scale factor, assuming that the browser
-    // compositor will map from DIPs back to physical pixels using its own
-    // device scale factor. However, the Android browser compositor always uses
-    // a device scale factor of 1.0, so we have to transform the delegated
-    // layer by the device scale to get it into the same physical pixel space as
-    // the rest of the UI.
-    const gfx::Display& display =
-        gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
-    float device_scale_factor = display.device_scale_factor();
-    gfx::Transform layer_scale(
-        device_scale_factor, 0.f, 0.f, device_scale_factor, 0.f, 0.f);
-    layer_->SetTransform(layer_scale);
   }
 
   base::Closure ack_callback =