Make the GM tool run GMs through an SkGPipe.

Add pipe to core gyp project.

Do not run samplerstress through the pipe, since its
custom MaskFilter will not draw correctly.

Fix an assert in SkGPipeWrite when writing a typeface.
Review URL: https://codereview.appspot.com/6276044

git-svn-id: http://skia.googlecode.com/svn/trunk@4139 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pipe/SkGPipeWrite.cpp b/src/pipe/SkGPipeWrite.cpp
index 08c6f49..5d35988 100644
--- a/src/pipe/SkGPipeWrite.cpp
+++ b/src/pipe/SkGPipeWrite.cpp
@@ -67,9 +67,9 @@
     if (writer) {
         writer->write32(size);
         SkAutoDataUnref data(stream.copyToData());
-        writer->write(data.data(), size);
+        writer->writePad(data.data(), size);
     }
-    return 4 + size;
+    return 4 + SkAlign4(size);
 }
 
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