Use SkPMColor4f throughout clear APIs

Bug: skia:
Change-Id: I5386e27edbcf39233880d869841a6632ecb9416c
Reviewed-on: https://skia-review.googlesource.com/c/168261
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/src/gpu/mock/GrMockGpuCommandBuffer.h b/src/gpu/mock/GrMockGpuCommandBuffer.h
index cad5836..a14fb64 100644
--- a/src/gpu/mock/GrMockGpuCommandBuffer.h
+++ b/src/gpu/mock/GrMockGpuCommandBuffer.h
@@ -51,7 +51,7 @@
                 const GrMesh[], int meshCount, const SkRect& bounds) override {
         ++fNumDraws;
     }
-    void onClear(const GrFixedClip&, GrColor) override {}
+    void onClear(const GrFixedClip&, const SkPMColor4f&) override {}
     void onClearStencilClip(const GrFixedClip&, bool insideStencilMask) override {}
 
     GrMockGpu* fGpu;