Add the ANGLEPlatform entry points to eglGetProcAddress

Reland with a Windows build fix.

We want to move the Chromium initialization of the ANGLE platform from
being Windows-specific to being EGL-specific. Because the mechanisms by
which the ANGLE library is loaded are OS-specific, it is inconvenient to
use dlsym and friends to get the ANGLEPlatform entry points. Instead
we expose the through eglGetProcAddress which is readily available in the
EGL-specific part of Chromium.

BUG=angleproject:1621

Change-Id: I022a39493756a3b5d1ed626fd05e74af3f043211
Reviewed-on: https://chromium-review.googlesource.com/410066
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>

BUILD.gn

@@ -277,6 +277,7 @@ config("libANGLE_config") {
   defines += [
     "GL_GLEXT_PROTOTYPES",
     "EGL_EGLEXT_PROTOTYPES",
+    "LIBANGLE_IMPLEMENTATION",
   ]
 
   if (is_win) {
@@ -300,7 +301,7 @@ static_library("libANGLE") {
 
   include_dirs = []
   libs = []
-  defines = [ "LIBANGLE_IMPLEMENTATION" ]
+  defines = []
   public_deps = [
     ":angle_common",
   ]

src/libGLESv2.gypi

@@ -741,6 +741,7 @@
                 ],
                 'defines':
                 [
+                    'LIBANGLE_IMPLEMENTATION',
                     'GL_GLEXT_PROTOTYPES',
                     'ANGLE_PRELOADED_D3DCOMPILER_MODULE_NAMES={ "d3dcompiler_47.dll", "d3dcompiler_46.dll", "d3dcompiler_43.dll" }',
                 ],

src/libGLESv2/entry_points_egl.cpp

@@ -24,6 +24,8 @@
 #include "common/debug.h"
 #include "common/version.h"
 
+#include "platform/Platform.h"
+
 #include <EGL/eglext.h>
 
 namespace egl
@@ -1275,6 +1277,9 @@ __eglMustCastToProperFunctionPointerType EGLAPIENTRY GetProcAddress(const char *
 #define INSERT_PROC_ADDRESS(ns, proc) \
     map[#ns #proc] = reinterpret_cast<__eglMustCastToProperFunctionPointerType>(ns::proc)
 
+#define INSERT_PROC_ADDRESS_NO_NS(name, proc) \
+    map[name] = reinterpret_cast<__eglMustCastToProperFunctionPointerType>(proc)
+
         // GLES2 core
         INSERT_PROC_ADDRESS(gl, ActiveTexture);
         INSERT_PROC_ADDRESS(gl, AttachShader);
@@ -1666,8 +1671,8 @@ __eglMustCastToProperFunctionPointerType EGLAPIENTRY GetProcAddress(const char *
         INSERT_PROC_ADDRESS(gl, UniformBlockBinding);
         INSERT_PROC_ADDRESS(gl, DrawArraysInstanced);
         INSERT_PROC_ADDRESS(gl, DrawElementsInstanced);
-        map["glFenceSync"] =
-            reinterpret_cast<__eglMustCastToProperFunctionPointerType>(gl::FenceSync_);
+        // FenceSync is the name of a class, the function has an added _ to prevent a name conflict.
+        INSERT_PROC_ADDRESS_NO_NS("glFenceSync", gl::FenceSync_);
         INSERT_PROC_ADDRESS(gl, IsSync);
         INSERT_PROC_ADDRESS(gl, DeleteSync);
         INSERT_PROC_ADDRESS(gl, ClientWaitSync);
@@ -1870,7 +1875,13 @@ __eglMustCastToProperFunctionPointerType EGLAPIENTRY GetProcAddress(const char *
         // EGL_EXT_swap_buffers_with_damage
         INSERT_PROC_ADDRESS(egl, SwapBuffersWithDamageEXT);
 
+        // angle::Platform related entry points
+        INSERT_PROC_ADDRESS_NO_NS("ANGLEPlatformInitialize", ANGLEPlatformInitialize);
+        INSERT_PROC_ADDRESS_NO_NS("ANGLEPlatformShutdown", ANGLEPlatformShutdown);
+
 #undef INSERT_PROC_ADDRESS
+#undef INSERT_PROC_ADDRESS_NO_NS
+
         return map;
     };