Add SetScale to PPB_WidgetDev, use scale for painting

In order to allow for HiDPI-aware scrollbars, this patch allows the plugin to
specify a scale factor used during widget paint operations.

The widgets (of which Scrollbar is the only current instance) will continue to
use the DIP coordinate system for events and sizing, which is consistent with
their WebKit implementation.

This change should maintain backward compat. with existing users of interface
'PPB_Wdiget(Dev);0.3'

BUG=140833
TEST=Run pre-built (with 0.3 interfaces) PDF plugin and verify scrollbars


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=152495

Review URL: https://chromiumcodereview.appspot.com/10824386

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@152889 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 12 insertions, 1 deletions

diff --git a/webkit/plugins/ppapi/ppb_scrollbar_impl.cc b/webkit/plugins/ppapi/ppb_scrollbar_impl.cc
index d6aa704..1a190bb 100644
--- a/webkit/plugins/ppapi/ppb_scrollbar_impl.cc
+++ b/webkit/plugins/ppapi/ppb_scrollbar_impl.cc
@@ -138,7 +138,10 @@ PP_Bool PPB_Scrollbar_Impl::PaintInternal(const gfx::Rect& rect,
   skia::PlatformCanvas* canvas = image->GetPlatformCanvas();
   if (!canvas || !scrollbar_.get())
     return PP_FALSE;
+  canvas->save();
+  canvas->scale(scale(), scale());
   scrollbar_->paint(webkit_glue::ToWebCanvas(canvas), rect);
+  canvas->restore();
 
 #if defined(OS_WIN)
   if (base::win::GetVersion() == base::win::VERSION_XP)
diff --git a/webkit/plugins/ppapi/ppb_widget_impl.cc b/webkit/plugins/ppapi/ppb_widget_impl.cc
index 306a1b5..8fe0386 100644
--- a/webkit/plugins/ppapi/ppb_widget_impl.cc
+++ b/webkit/plugins/ppapi/ppb_widget_impl.cc
@@ -22,7 +22,8 @@ namespace webkit {
 namespace ppapi {
 
 PPB_Widget_Impl::PPB_Widget_Impl(PP_Instance instance)
-    : Resource(::ppapi::OBJECT_IS_IMPL, instance) {
+    : Resource(::ppapi::OBJECT_IS_IMPL, instance),
+      scale_(1.0f) {
   memset(&location_, 0, sizeof(location_));
 }
 
@@ -59,6 +60,10 @@ void PPB_Widget_Impl::SetLocation(const PP_Rect* location) {
   SetLocationInternal(location);
 }
 
+void PPB_Widget_Impl::SetScale(float scale) {
+  scale_ = scale;
+}
+
 void PPB_Widget_Impl::Invalidate(const PP_Rect* dirty) {
   PluginInstance* plugin_instance = ResourceHelper::GetPluginInstance(this);
   if (!plugin_instance)
diff --git a/webkit/plugins/ppapi/ppb_widget_impl.h b/webkit/plugins/ppapi/ppb_widget_impl.h
index caaab2a..7fd143e 100644
--- a/webkit/plugins/ppapi/ppb_widget_impl.h
+++ b/webkit/plugins/ppapi/ppb_widget_impl.h
@@ -37,6 +37,7 @@ class PPB_Widget_Impl : public ::ppapi::Resource,
   virtual PP_Bool HandleEvent(PP_Resource pp_input_event) OVERRIDE;
   virtual PP_Bool GetLocation(PP_Rect* location) OVERRIDE;
   virtual void SetLocation(const PP_Rect* location) OVERRIDE;
+  virtual void SetScale(float scale) OVERRIDE;
 
   // Notifies the plugin instance that the given rect needs to be repainted.
   void Invalidate(const PP_Rect* dirty);
@@ -48,9 +49,11 @@ class PPB_Widget_Impl : public ::ppapi::Resource,
   virtual void SetLocationInternal(const PP_Rect* location) = 0;
 
   PP_Rect location() const { return location_; }
+  float scale() const { return scale_; }
 
  private:
   PP_Rect location_;
+  float scale_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_Widget_Impl);
 };