Fix uninitialized variable in pixel_dump.cc

Bug: 849142
Change-Id: I1a758908af5e765dd69868a8d045664d208346d3
Reviewed-on: https://chromium-review.googlesource.com/1086229Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#564678}

content/shell/test_runner/pixel_dump.cc

@@ -187,11 +187,11 @@ void CopyImageAtAndCapturePixels(
   blink::Platform::Current()->GetConnector()->BindInterface(
       blink::Platform::Current()->GetBrowserServiceName(), &clipboard);
 
-  uint64_t sequence_number_before;
+  uint64_t sequence_number_before = 0;
   clipboard->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE,
                                &sequence_number_before);
   web_frame->CopyImageAt(blink::WebPoint(x, y));
-  uint64_t sequence_number_after;
+  uint64_t sequence_number_after = 0;
   clipboard->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE,
                                &sequence_number_after);
   if (sequence_number_before == sequence_number_after) {