Support JavaScript window.moveTo/By() and resizeTo/By() (fixes #698)

Adds new CefDisplayHandler::OnContentsBoundsChange and
CefDisplayHandler::GetRootWindowScreenRect callbacks.

cefclient: Implement the above callbacks and call
CefBrowserHost::NotifyScreenInfoChanged when the root window
bounds change.

cefclient: osr: Use real screen bounds by default. Pass
`--fake-screen-bounds` for the old default behavior.

Load https://tests/window in cefclient for additional
implementation details and usage examples.

tests/cefclient/browser/test_runner.cc

@@ -146,7 +146,9 @@ void RunNewWindowTest(CefRefPtr<CefBrowser> browser) {
 
 void RunPopupWindowTest(CefRefPtr<CefBrowser> browser) {
   browser->GetMainFrame()->ExecuteJavaScript(
-      "window.open('https://www.google.com');", "about:blank", 0);
+      "window.open('https://www.google.com', 'google', "
+      "'left=100,top=100,width=600,height=400');",
+      "about:blank", 0);
 }
 
 void RunDialogWindowTest(CefRefPtr<CefBrowser> browser) {
@@ -269,8 +271,8 @@ void PromptDSF(CefRefPtr<CefBrowser> browser) {
 
   // Format the default value string.
   std::stringstream ss;
-  ss << RootWindow::GetForBrowser(browser->GetIdentifier())
-            ->GetDeviceScaleFactor();
+  ss << *RootWindow::GetForBrowser(browser->GetIdentifier())
+             ->GetDeviceScaleFactor();
 
   Prompt(browser, kPromptDSF, "Enter Device Scale Factor", ss.str());
 }