Move most of the transform logic into the primitive processors

BUG=skia:

Review URL: https://codereview.chromium.org/822423004
diff --git a/src/gpu/effects/GrBitmapTextGeoProc.h b/src/gpu/effects/GrBitmapTextGeoProc.h
index 85e4f42..399678a 100644
--- a/src/gpu/effects/GrBitmapTextGeoProc.h
+++ b/src/gpu/effects/GrBitmapTextGeoProc.h
@@ -40,7 +40,8 @@
                                    const GrGLCaps& caps,
                                    GrProcessorKeyBuilder* b) const SK_OVERRIDE;
 
-    GrGLGeometryProcessor* createGLInstance(const GrBatchTracker& bt) const SK_OVERRIDE;
+    virtual GrGLPrimitiveProcessor* createGLInstance(const GrBatchTracker& bt,
+                                                     const GrGLCaps& caps) const SK_OVERRIDE;
 
     void initBatchTracker(GrBatchTracker*, const InitBT&) const SK_OVERRIDE;
     bool onCanMakeEqual(const GrBatchTracker&,