Add RenderView ResetDeviceColorProfileForTesting

Provide a method to reset the device color profile for tests, and
make TestRunner call it prior to each layout test.

This to reset the Page color profile to its default state, to let
Page choose the default color profile, rather than TestRunner.

BUG=369787,368663

Review URL: https://codereview.chromium.org/561453004

Cr-Commit-Position: refs/heads/master@{#295097}
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index d9f620d5..8cf0ae0 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -1659,6 +1659,12 @@
   return true;
 }
 
+void RenderWidget::ResetDeviceColorProfileForTesting() {
+  if (!device_color_profile_.empty())
+    device_color_profile_.clear();
+  device_color_profile_.push_back('0');
+}
+
 void RenderWidget::OnOrientationChange() {
 }