Retract GrTexture*.h & GrRenderTarget*.h from other headers

This does push some additional work (& includes) into the .cpp files.

Change-Id: I27c847e371802270d13594dcc22aae44039990bb
Reviewed-on: https://skia-review.googlesource.com/19660
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/effects/GrMatrixConvolutionEffect.cpp b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
index 776eff0..d1726a0 100644
--- a/src/gpu/effects/GrMatrixConvolutionEffect.cpp
+++ b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
@@ -6,6 +6,7 @@
  */
 #include "GrMatrixConvolutionEffect.h"
 
+#include "GrTexture.h"
 #include "GrTextureProxy.h"
 #include "glsl/GrGLSLFragmentProcessor.h"
 #include "glsl/GrGLSLFragmentShaderBuilder.h"