SkDumpCanvas is going away. Stop excluding it from building.

Change-Id: I4b7e26985d4f3a66111cf70135c78fca4beed73a
Reviewed-on: https://chromium-review.googlesource.com/957483Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Cr-Commit-Position: refs/heads/master@{#542273}

skia/BUILD.gn

@@ -351,7 +351,6 @@ component("skia") {
   # Remove unused util sources.
   sources -= [
     "//third_party/skia/src/utils/SkCamera.cpp",
-    "//third_party/skia/src/utils/SkDumpCanvas.cpp",
     "//third_party/skia/src/utils/SkFrontBufferedStream.cpp",
     "//third_party/skia/src/utils/SkInterpolator.cpp",
     "//third_party/skia/src/utils/SkOSPath.cpp",