cc: Add point-based UV coordinate on TextureLayer

cc/texture_draw_quad.cc

Index: cc/texture_draw_quad.cc
diff --git a/cc/texture_draw_quad.cc b/cc/texture_draw_quad.cc
index f652707f6cd3555803f6c3fdc2fdfe3bdd25451c..2a0dfe4929b03cd92e88eaa76703430f46cc21cc 100644
--- a/cc/texture_draw_quad.cc
+++ b/cc/texture_draw_quad.cc
@@ -5,6 +5,7 @@
 #include "cc/texture_draw_quad.h"
 
 #include "base/logging.h"
+#include "ui/gfx/vector2d_f.h"
 
 namespace cc {
 
@@ -21,7 +22,8 @@ scoped_ptr<TextureDrawQuad> TextureDrawQuad::Create() {
 void TextureDrawQuad::SetNew(const SharedQuadState* shared_quad_state,
                              gfx::Rect rect, gfx::Rect opaque_rect,
                              unsigned resource_id, bool premultiplied_alpha,
-                             const gfx::RectF& uv_rect,
+                             gfx::PointF uv_top_left,
+                             gfx::PointF uv_bottom_right,
                              const float vertex_opacity[4], bool flipped) {
   gfx::Rect visible_rect = rect;
   bool needs_blending = vertex_opacity[0] != 1.0f || vertex_opacity[1] != 1.0f
@@ -30,7 +32,8 @@ void TextureDrawQuad::SetNew(const SharedQuadState* shared_quad_state,
                    opaque_rect, visible_rect, needs_blending);
   this->resource_id = resource_id;
   this->premultiplied_alpha = premultiplied_alpha;
-  this->uv_rect = uv_rect;
+  this->uv_top_left = uv_top_left;
+  this->uv_bottom_right = uv_bottom_right;
   this->vertex_opacity[0] = vertex_opacity[0];
   this->vertex_opacity[1] = vertex_opacity[1];
   this->vertex_opacity[2] = vertex_opacity[2];
@@ -42,13 +45,15 @@ void TextureDrawQuad::SetAll(const SharedQuadState* shared_quad_state,
                              gfx::Rect rect, gfx::Rect opaque_rect,
                              gfx::Rect visible_rect, bool needs_blending,
                              unsigned resource_id, bool premultiplied_alpha,
-                             const gfx::RectF& uv_rect,
+                             gfx::PointF uv_top_left,
+                             gfx::PointF uv_bottom_right,
                              const float vertex_opacity[4], bool flipped) {
   DrawQuad::SetAll(shared_quad_state, DrawQuad::TEXTURE_CONTENT, rect,
                    opaque_rect, visible_rect, needs_blending);
   this->resource_id = resource_id;
   this->premultiplied_alpha = premultiplied_alpha;
-  this->uv_rect = uv_rect;
+  this->uv_top_left = uv_top_left;
+  this->uv_bottom_right = uv_bottom_right;
   this->vertex_opacity[0] = vertex_opacity[0];
   this->vertex_opacity[1] = vertex_opacity[1];
   this->vertex_opacity[2] = vertex_opacity[2];
@@ -85,18 +90,24 @@ bool TextureDrawQuad::PerformClipping() {
   gfx::RectF clippedRect = IntersectRects(rectF, clipRect());
   if (clippedRect.IsEmpty()) {
     rect = gfx::Rect();
-    uv_rect = gfx::RectF();
+    uv_top_left = gfx::PointF();
+    uv_bottom_right = gfx::PointF();
     return true;
   }
 
   // Create a new uv-rect by clipping the old one to the new bounds.
-  uv_rect = gfx::RectF(
-      uv_rect.x()
-          + uv_rect.width() / rectF.width() * (clippedRect.x() - rectF.x()),
-      uv_rect.y()
-          + uv_rect.height() / rectF.height() * (clippedRect.y() - rectF.y()),
-      uv_rect.width() / rectF.width() * clippedRect.width(),
-      uv_rect.height() / rectF.height() * clippedRect.height());
+  gfx::Vector2dF uv_scale(uv_bottom_right - uv_top_left);
+  uv_scale.Scale(1.f / rectF.width(), 1.f / rectF.height());
+  uv_bottom_right = uv_top_left +
+      gfx::ScaleVector2d(
+          clippedRect.bottom_right() - rectF.origin(),
+          uv_scale.x(),
+          uv_scale.y());
+  uv_top_left = uv_top_left +
+      gfx::ScaleVector2d(
+          clippedRect.origin() - rectF.origin(),
+          uv_scale.x(),
+          uv_scale.y());
 
   // Indexing according to the quad vertex generation:
   // 1--2