Remove unsafe mode to enable es3 api by default for WebGL2 and ES3 context

ui/gl/gl_switches.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GL_GL_SWITCHES_H_
 #define UI_GL_GL_SWITCHES_H_
 
 // Defines all the command-line switches used by ui/gl.
 
 #include "ui/gl/gl_export.h"
@@ skipping 28 matching lines @@
 GL_EXPORT extern const char kGpuNoContextLost[];
 GL_EXPORT extern const char kDisableDirectComposition[];
 
 GL_EXPORT extern const char kSupportsDualGpus[];
 
 GL_EXPORT extern const char kUseANGLE[];
 GL_EXPORT extern const char kUseGL[];
 GL_EXPORT extern const char kSwiftShaderPath[];
 GL_EXPORT extern const char kTestGLLib[];
 GL_EXPORT extern const char kUseGpuInTests[];
-GL_EXPORT extern const char kEnableUnsafeES3APIs[];
 GL_EXPORT extern const char kEnableSgiVideoSync[];
 GL_EXPORT extern const char kDisableGLExtensions[];
 GL_EXPORT extern const char kEnableSwapBuffersWithDamage[];
 
 // These flags are used by the test harness code, not passed in by users.
 GL_EXPORT extern const char kDisableGLDrawingForTests[];
 GL_EXPORT extern const char kOverrideUseGLWithOSMesaForTests[];
 
 GL_EXPORT extern const char* kGLSwitchesCopiedFromGpuProcessHost[];
 GL_EXPORT extern const int kGLSwitchesCopiedFromGpuProcessHostNumSwitches;
 
 }  // namespace switches
 
 #endif  // UI_GL_GL_SWITCHES_H_