cc: Add dummy varying/uniform to fix solid color quads.

These shaders are broken on certain Android devices.
This is a minimal fix first, where the real problem
likely is a driver bug or shader compiler bug.

BUG=240602

Review URL: https://chromiumcodereview.appspot.com/14995021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@200484 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 20 insertions, 0 deletions

diff --git a/cc/output/shader.cc b/cc/output/shader.cc
index c4ffd0e..cee3474 100644
--- a/cc/output/shader.cc
+++ b/cc/output/shader.cc
@@ -351,17 +351,37 @@ void VertexShaderQuad::Init(WebGraphicsContext3D* context,
 }
 
 std::string VertexShaderQuad::GetShaderString() const {
+#if defined(OS_ANDROID)
+// TODO(epenner): Find the cause of this 'quad' uniform
+// being missing if we don't add dummy variables.
+// http://crbug.com/240602
   return VERTEX_SHADER(
     attribute TexCoordPrecision vec4 a_position;
     attribute float a_index;
     uniform mat4 matrix;
     uniform TexCoordPrecision vec2 quad[4];
+    uniform TexCoordPrecision vec2 dummy_uniform;
+    varying TexCoordPrecision vec2 dummy_varying;
     void main() {
       vec2 pos = quad[int(a_index)];  // NOLINT
       gl_Position = matrix * vec4(
           pos.x, pos.y, a_position.z, a_position.w);
+      dummy_varying = dummy_uniform;
     }
   );  // NOLINT(whitespace/parens)
+#else
+  return VERTEX_SHADER(
+    attribute TexCoordPrecision vec4 a_position;
+    attribute float a_index;
+    uniform mat4 matrix;
+    uniform TexCoordPrecision vec2 quad[4];
+    void main() {
+      vec2 pos = quad[int(a_index)];  // NOLINT
+      gl_Position = matrix * vec4(
+          pos.x, pos.y, a_position.z, a_position.w);
+    }
+  );  // NOLINT(whitespace/parens)
+#endif
 }
 
 VertexShaderQuadTex::VertexShaderQuadTex()