Add chrome runtime support for more callbacks and ceftests (see issue #2969)

This change adds support for:
- Protocol and request handling.
- Loading and navigation events.
- Display and focus events.
- Mouse/keyboard events.
- Popup browsers.
- Callbacks in the renderer process.
- Misc. functionality required for ceftests.

This change also adds a new CefBrowserProcessHandler::GetCookieableSchemes
callback for configuring global state that will be applied to all
CefCookieManagers by default. This global callback is currently required by the
chrome runtime because the primary ProfileImpl is created via
ChromeBrowserMainParts::PreMainMessageLoopRun (CreatePrimaryProfile) before
OnContextCreated can be called.

ProfileImpl will use the "C:\Users\[user]\AppData\Local\CEF\User Data\Default"
directory by default (on Windows). Cookies may persist in this directory when
running ceftests and may need to be manually deleted if those tests fail.

Remaining work includes:
- Support for client-created request contexts.
- Embedding the browser in a Views hierarchy (cefclient support).
- TryCloseBrowser and DoClose support.
- Most of the CefSettings configuration.
- DevTools protocol and window control (ShowDevTools, ExecuteDevToolsMethod).
- CEF-specific WebUI pages (about, license, webui-hosts).
- Context menu customization (CefContextMenuHandler).
- Auto resize (SetAutoResizeEnabled).
- Zoom settings (SetZoomLevel).
- File dialog runner (RunFileDialog).
- File and JS dialog handlers (CefDialogHandler, CefJSDialogHandler).
- Extension loading (LoadExtension, etc).
- Plugin loading (OnBeforePluginLoad).
- Widevine loading (CefRegisterWidevineCdm).
- PDF and print preview does not display.
- Crash reporting is untested.
- Mac: Web content loads but does not display.

The following ceftests are now passing when run with the
"--enable-chrome-runtime" command-line flag:

CorsTest.*
DisplayTest.*:-DisplayTest.AutoResize
DOMTest.*
DraggableRegionsTest.*
ImageTest.*
MessageRouterTest.*
NavigationTest.*
ParserTest.*
RequestContextTest.*Global*
RequestTest.*
ResourceManagerTest.*
ResourceRequestHandlerTest.*
ResponseTest.*
SchemeHandlerTest.*
ServerTest.*
StreamResourceHandlerTest.*
StreamTest.*
StringTest.*
TaskTest.*
TestServerTest.*
ThreadTest.*
URLRequestTest.*Global*
V8Test.*:-V8Test.OnUncaughtExceptionDevTools
ValuesTest.*
WaitableEventTest.*
XmlReaderTest.*
ZipReaderTest.*

include/cef_browser_process_handler.h

@@ -51,6 +51,23 @@
 /*--cef(source=client,no_debugct_check)--*/
 class CefBrowserProcessHandler : public virtual CefBaseRefCounted {
  public:
+  ///
+  // Called on the browser process UI thread to retrieve the list of schemes
+  // that should support cookies. If |include_defaults| is true the default
+  // schemes ("http", "https", "ws" and "wss") will also be supported. Providing
+  // an empty |schemes| value and setting |include_defaults| to false will
+  // disable all loading and saving of cookies.
+  //
+  // This state will apply to the CefCookieManager associated with the global
+  // CefRequestContext. It will also be used as the initial state for any new
+  // CefRequestContexts created by the client. After creating a new
+  // CefRequestContext the CefCookieManager::SetSupportedSchemes method may be
+  // called on the associated CefCookieManager to futher override these values.
+  ///
+  /*--cef()--*/
+  virtual void GetCookieableSchemes(std::vector<CefString>& schemes,
+                                    bool& include_defaults) {}
+
   ///
   // Called on the browser process UI thread immediately after the CEF context
   // has been initialized.