[devtools] Add a command to emulate the default background color.

third_party/WebKit/Source/web/InspectorEmulationAgent.cpp

Index: third_party/WebKit/Source/web/InspectorEmulationAgent.cpp
diff --git a/third_party/WebKit/Source/web/InspectorEmulationAgent.cpp b/third_party/WebKit/Source/web/InspectorEmulationAgent.cpp
index f661594577ef716c1108aaf48cbcc8102f487974..0bee22ee3d362c65e58211cca084cd0111466f67 100644
--- a/third_party/WebKit/Source/web/InspectorEmulationAgent.cpp
+++ b/third_party/WebKit/Source/web/InspectorEmulationAgent.cpp
@@ -7,13 +7,16 @@
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
+#include "core/inspector/protocol/DOM.h"
 #include "core/page/Page.h"
 #include "platform/geometry/DoubleRect.h"
+#include "platform/graphics/Color.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebFloatPoint.h"
 #include "public/platform/WebThread.h"
 #include "public/platform/WebViewScheduler.h"
 #include "web/DevToolsEmulator.h"
+#include "web/WebFrameWidgetBase.h"
 #include "web/WebLocalFrameImpl.h"
 #include "web/WebViewImpl.h"
 
@@ -169,6 +172,15 @@ void InspectorEmulationAgent::virtualTimeBudgetExpired() {
   frontend()->virtualTimeBudgetExpired();
 }
 
+Response InspectorEmulationAgent::setDefaultBackgroundColor(
+    std::unique_ptr<protocol::DOM::RGBA> color) {

[dgozman, 2017/01/20 17:57:07]

I'd like this to be optional, so that passing nothing resets to default one.

[Eric Seckler, 2017/01/23 18:06:24]

Done. Also renamed the command to overrideDefaultBackgroundColor

+  int alpha = lroundf(255.0f * color->getA(1.0f));
+  // Clamping of values is done by Color() constructor.
+  m_webLocalFrameImpl->frameWidget()->setBaseBackgroundColor(

[dgozman, 2017/01/20 17:57:07]

We use WebViewImpl::setBackgroundColorOverride in DevToolsEmulator. Should we
merge two?

[Eric Seckler, 2017/01/23 18:06:24]

Sounds good. I'm trying to use this method now, but it seems that it doesn't
have the effect I'm looking for - or I'm doing something wrong. The test, at
least, doesn't pass anymore, because the page stays white.

Can you spot a mistake? :)

[dgozman, 2017/01/23 20:27:04]

Hmm... Looks like they are different. The one we use in device emulation is for
area around the page, while you want to override the page background itself.
Sorry for confusion.

[Eric Seckler, 2017/01/24 14:08:26]

Ah, okay, that makes sense then. Back to setBaseBackgroundColor it is :)

FYI, I'm now also storing this override in the agent's state to support
restoring and resetting it.

+      Color(color->getR(), color->getG(), color->getB(), alpha).rgb());
+  return Response::OK();
+}
+
 DEFINE_TRACE(InspectorEmulationAgent) {
   visitor->trace(m_webLocalFrameImpl);
   InspectorBaseAgent::trace(visitor);