Add a --use-angle flag for selecting the ANGLE renderer.

ui/gl/gl_surface_egl.h

Index: ui/gl/gl_surface_egl.h
diff --git a/ui/gl/gl_surface_egl.h b/ui/gl/gl_surface_egl.h
index 614a78403c5e971fad00d04ac99b298a52f1b98d..c64385527640ced6f8e7a12d09768e444d2bf75c 100644
--- a/ui/gl/gl_surface_egl.h
+++ b/ui/gl/gl_surface_egl.h
@@ -11,6 +11,7 @@
 
 #include <string>
 
+#include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/time/time.h"
 #include "ui/gfx/geometry/size.h"
@@ -23,6 +24,21 @@ namespace gfx {
 // Get default EGL display for GLSurfaceEGL (differs by platform).
 EGLNativeDisplayType GetPlatformDefaultEGLNativeDisplay();
 
+enum DisplayType {
+  DEFAULT,
+  SWIFT_SHADER,
+  ANGLE_WARP,
+  ANGLE_D3D9,
+  ANGLE_D3D11,
+  ANGLE_OPENGL,
+  ANGLE_OPENGLES,
+};
+
+GL_EXPORT void GetEGLInitDisplays(bool supports_angle_d3d,
+                                  bool supports_angle_opengl,
+                                  const base::CommandLine* command_line,
+                                  std::vector<DisplayType>* init_displays);
+
 // Interface for EGL surface.
 class GL_EXPORT GLSurfaceEGL : public GLSurface {
  public: