[Chromoting] Implement GlRenderer

remoting/client/gl_math.cc

Index: remoting/client/gl_math.cc
diff --git a/remoting/client/gl_math.cc b/remoting/client/gl_math.cc
index b223ff367344ee5d63becbc75c2940840c04a704..85f33693cdd7993da1a60778b4b6b156ce38b25a 100644
--- a/remoting/client/gl_math.cc
+++ b/remoting/client/gl_math.cc
@@ -8,15 +8,21 @@
 
 namespace {
 
-// | m0, m1, m2, |   | Scale_x  0        Offset_x |
-// | m3, m4, m5, | = | 0        Scale_y  Offset_y |
+// | m0, m1, m2, |   | Scale_x  Skew_x   Offset_x |
+// | m3, m4, m5, | = | Skew_y   Scale_y  Offset_y |
 // | m6, m7, m8  |   | 0        0        1        |
 
 const int kXScaleKey = 0;
-const int kYScaleKey = 4;
+const int kXSkewKey = 1;
 const int kXOffsetKey = 2;
+
+const int kYSkewKey = 3;
+const int kYScaleKey = 4;
 const int kYOffsetKey = 5;
 
+const int kXOffsetTransposedKey = 6;
+const int kYOffsetTransposedKey = 7;
+
 }  // namespace
 
 namespace remoting {
@@ -32,6 +38,12 @@ void NormalizeTransformationMatrix(int view_width,
   (*matrix)[kYOffsetKey] /= view_height;
 }
 
+void TransposeTransformationMatrix(std::array<float, 9>* matrix) {
+  std::swap((*matrix)[kXOffsetKey], (*matrix)[kXOffsetTransposedKey]);
+  std::swap((*matrix)[kYOffsetKey], (*matrix)[kYOffsetTransposedKey]);
+  std::swap((*matrix)[kXSkewKey], (*matrix)[kYSkewKey]);
+}
+
 void FillRectangleVertexPositions(float left,
                                   float top,
                                   float width,