Refactor VR Shell Input. Locks input to click/scroll targets.

chrome/browser/android/vr_shell/textures/ui_texture.h

Index: chrome/browser/android/vr_shell/textures/ui_texture.h
diff --git a/chrome/browser/android/vr_shell/textures/ui_texture.h b/chrome/browser/android/vr_shell/textures/ui_texture.h
index f1529b3dd8ccc4de94ff1d78fe2854354c8f5a1e..ab6e06d0cb9425d383ddce4c485f11634a344d42 100644
--- a/chrome/browser/android/vr_shell/textures/ui_texture.h
+++ b/chrome/browser/android/vr_shell/textures/ui_texture.h
@@ -27,6 +27,8 @@ class UiTexture {
   void DrawAndLayout(SkCanvas* canvas, const gfx::Size& texture_size);
   virtual gfx::Size GetPreferredTextureSize(int maximum_width) const = 0;
   virtual gfx::SizeF GetDrawnSize() const = 0;
+  // Returns true if the state changed.

[cjgrant, 2017/05/10 20:16:25]

Are you adding this here as a general purpose means of checking if some
arbitrary property changed?  I find it really confusing for the bit of help it's
offering.  It could just be a pair of get/set flags methods, and subclasses
could check and update as needed.  At a minimum, it should be renamed
UpdateDrawFlags() or something, as the texture is not actually being updated.

[mthiesse, 2017/05/10 21:09:08]

Changed to SetDrawFlags, missing getter was an oversight.

The purpose here is to make it easier to avoid re-drawing when not necessary.

We should flesh this out more in future CLs, as it's possible the state changes,
but the element still doesn't need to redraw.

+  bool Update(int draw_flags);
 
  protected:
   virtual void Draw(SkCanvas* canvas, const gfx::Size& texture_size) = 0;
@@ -34,6 +36,8 @@ class UiTexture {
   static bool IsRTL();
   static gfx::FontList GetDefaultFontList(int size);
   static gfx::FontList GetFontList(int size, base::string16 text);
+
+  int draw_flags_ = 0;
 };
 
 }  // namespace vr_shell