Add configuration_changed event and set_background_opacity request.

components/exo/shell_surface.h

Index: components/exo/shell_surface.h
diff --git a/components/exo/shell_surface.h b/components/exo/shell_surface.h
index 525e7c2fee40b82ce8d15fece2762262df08470b..8de8f3ba8660460c8fe675eda848e1726368dacb 100644
--- a/components/exo/shell_surface.h
+++ b/components/exo/shell_surface.h
@@ -10,6 +10,7 @@
 #include <string>
 
 #include "ash/common/wm/window_state_observer.h"
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "components/exo/surface_delegate.h"
@@ -147,6 +148,9 @@ class ShellSurface : public SurfaceDelegate,
   // the shadow.
   void SetRectangularShadow(const gfx::Rect& content_bounds);
 
+  // Set the pacity of the background for the window that has a shadow.
+  void SetBackgroundOpacity(float opacity);
+
   // Set scale factor for surface. The scale factor will be applied to surface
   // and all descendants.
   void SetScale(double scale);
@@ -216,6 +220,7 @@ class ShellSurface : public SurfaceDelegate,
  private:
   class ScopedConfigure;
   class ScopedAnimationsDisabled;
+  FRIEND_TEST_ALL_PREFIXES(ShellSurfaceTest, ShadowStartMaximized);
 
   // Surface state associated with each configure request.
   struct Config {
@@ -288,6 +293,7 @@ class ShellSurface : public SurfaceDelegate,
   std::unique_ptr<ScopedAnimationsDisabled> scoped_animations_disabled_;
   int top_inset_height_ = 0;
   int pending_top_inset_height_ = 0;
+  float background_opacity_ = 1.0;
 
   DISALLOW_COPY_AND_ASSIGN(ShellSurface);
 };