chrome: Add support for Alloy style browsers and windows (see #3681)

Split the Alloy runtime into bootstrap and style components. Support
creation of Alloy style browsers and windows with the Chrome runtime.
Chrome runtime (`--enable-chrome-runtime`) + Alloy style
(`--use-alloy-style`) supports Views (`--use-views`), native parent
(`--use-native`) and windowless rendering
(`--off-screen-rendering-enabled`).

Print preview is supported in all cases except with windowless rendering
on all platforms and native parent on MacOS. It is disabled by default
with Alloy style for legacy compatibility. Where supported it can be
enabled or disabled globally using `--[enable|disable]-print-preview` or
configured on a per-RequestContext basis using the
`printing.print_preview_disabled` preference. It also behaves as
expected when triggered via the PDF viewer print button.

Chrome runtime + Alloy style behavior differs from Alloy runtime in the
following significant ways:

- Supports Chrome error pages by default.
- DevTools popups are Chrome style only (cannot be windowless).
- The Alloy extension API will not supported.

Chrome runtime + Alloy style passes all expected Alloy ceftests except
the following:

- `DisplayTest.AutoResize` (Alloy extension API not supported)
- `DownloadTest.*` (Download API not yet supported)
- `ExtensionTest.*` (Alloy extension API not supported)

This change also adds Chrome runtime support for
CefContextMenuHandler::RunContextMenu (see #3293).

This change also explicitly blocks (and doesn't retry) FrameAttached
requests from PDF viewer and print preview excluded frames (see #3664).

Known issues specific to Chrome runtime + Alloy style:
- DevTools popup with windowless rendering doesn't load successfully.
  Use windowed rendering or remote debugging as a workaround.
- Chrome style Window with Alloy style BrowserView (`--use-alloy-style
  --use-chrome-style-window`) does not show Chrome theme changes.

To test:
- Run `ceftests --enable-chrome-runtime --use-alloy-style
       [--use-chrome-style-window] [--use-views|--use-native]
       --gtest_filter=...`
- Run `cefclient --enable-chrome-runtime --use-alloy-style
       [--use-chrome-style-window]
       [--use-views|--use-native|--off-screen-rendering-enabled]`
- Run `cefsimple --enable-chrome-runtime --use-alloy-style [--use-views]`

tests/ceftests/test_util.h

@@ -14,6 +14,8 @@
 #include "include/cef_request_context.h"
 #include "include/cef_response.h"
 #include "include/cef_values.h"
+#include "include/views/cef_browser_view.h"
+#include "include/views/cef_window.h"
 #include "tests/ceftests/test_suite.h"
 
 CefTime CefTimeFrom(CefBaseTime value);
@@ -86,7 +88,25 @@ inline bool IsTestRequestContextModeCustom(TestRequestContextMode mode) {
 bool TestOldResourceAPI();
 
 // Returns true if the Chrome runtime is enabled.
-bool IsChromeRuntimeEnabled();
+bool IsChromeBootstrap();
+
+// Returns true if Views should be used as a the global default.
+bool UseViewsGlobal();
+
+// Returns true if Alloy style browser should be used as the global default.
+bool UseAlloyStyleBrowserGlobal();
+
+// Returns true if Alloy style window should be used as the global default.
+// Only used in combination with Views.
+bool UseAlloyStyleWindowGlobal();
+
+// Determine the Views window title based on the style of |window| and
+// optionally |browser_view|.
+std::string ComputeViewsWindowTitle(CefRefPtr<CefWindow> window,
+                                    CefRefPtr<CefBrowserView> browser_view);
+
+// Determine the native window title based on |use_alloy_style|.
+std::string ComputeNativeWindowTitle(bool use_alloy_style);
 
 // Returns true if BFCache is enabled.
 bool IsBFCacheEnabled();