Make Platform methods global.

This will allow them to be imported dynamically without name
mangling. This is necessary because sometimes SwiftShader
overrides libGLESv2 and libEGL, so we need to determine at
run-time if we are running with "actual" ANGLE.

BUG=466735

Change-Id: I396d717b79066feb8ed0d577ee7386b33eb1d160
Reviewed-on: https://chromium-review.googlesource.com/259954
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>

include/platform/Platform.h

@@ -20,10 +20,6 @@ class Platform
 {
   public:
 
-    ANGLE_EXPORT static void initialize(Platform*);
-    ANGLE_EXPORT static void shutdown();
-    ANGLE_EXPORT static Platform *current();
-
     // Tracing --------
 
     typedef uint64_t TraceEventHandle;
@@ -104,4 +100,13 @@ class Platform
 
 }
 
+typedef void(*ANGLEPlatformInitializeFunc)(angle::Platform*);
+ANGLE_EXPORT void ANGLEPlatformInitialize(angle::Platform*);
+
+typedef void (*ANGLEPlatformShutdownFunc)();
+ANGLE_EXPORT void ANGLEPlatformShutdown();
+
+typedef angle::Platform *(*ANGLEPlatformCurrentFunc)();
+ANGLE_EXPORT angle::Platform *ANGLEPlatformCurrent();
+
 #endif // ANGLE_PLATFORM_H

src/libANGLE/Display.cpp

@@ -55,14 +55,14 @@ DefaultPlatform *defaultPlatform = nullptr;
 
 void InitDefaultPlatformImpl()
 {
-    if (angle::Platform::current() == nullptr)
+    if (ANGLEPlatformCurrent() == nullptr)
     {
         if (defaultPlatform == nullptr)
         {
             defaultPlatform = new DefaultPlatform();
         }
 
-        angle::Platform::initialize(defaultPlatform);
+        ANGLEPlatformInitialize(defaultPlatform);
     }
 }
 
@@ -70,9 +70,9 @@ void DeinitDefaultPlatformImpl()
 {
     if (defaultPlatform != nullptr)
     {
-        if (angle::Platform::current() == defaultPlatform)
+        if (ANGLEPlatformCurrent() == defaultPlatform)
         {
-            angle::Platform::shutdown();
+            ANGLEPlatformShutdown();
         }
 
         SafeDelete(defaultPlatform);

src/libANGLE/Platform.cpp

@@ -9,33 +9,27 @@
 #include <platform/Platform.h>
 
 #include "common/debug.h"
-#include "platform/Platform.h"
-
-namespace angle
-{
 
 namespace
 {
-Platform *currentPlatform = nullptr;
+angle::Platform *currentPlatform = nullptr;
 }
 
 // static
-ANGLE_EXPORT Platform *Platform::current()
+ANGLE_EXPORT angle::Platform *ANGLEPlatformCurrent()
 {
     return currentPlatform;
 }
 
 // static
-ANGLE_EXPORT void Platform::initialize(Platform *platformImpl)
+ANGLE_EXPORT void ANGLEPlatformInitialize(angle::Platform *platformImpl)
 {
     ASSERT(platformImpl != nullptr);
     currentPlatform = platformImpl;
 }
 
 // static
-ANGLE_EXPORT void Platform::shutdown()
+ANGLE_EXPORT void ANGLEPlatformShutdown()
 {
     currentPlatform = nullptr;
 }
-
-}

src/libANGLE/renderer/d3d/DisplayD3D.cpp

@@ -109,7 +109,7 @@ egl::Error CreateRendererD3D(egl::Display *display, RendererD3D **outRenderer)
             {
                 ASSERT(result.getID() >= 0 && result.getID() < NUM_D3D11_INIT_ERRORS);
 
-                angle::Platform *platform = angle::Platform::current();
+                angle::Platform *platform = ANGLEPlatformCurrent();
                 platform->histogramEnumeration("GPU.ANGLE.D3D11InitializeResult",
                                                result.getID(), NUM_D3D11_INIT_ERRORS);
             }
@@ -120,7 +120,7 @@ egl::Error CreateRendererD3D(egl::Display *display, RendererD3D **outRenderer)
             {
                 ASSERT(result.getID() >= 0 && result.getID() < NUM_D3D9_INIT_ERRORS);
 
-                angle::Platform *platform = angle::Platform::current();
+                angle::Platform *platform = ANGLEPlatformCurrent();
                 platform->histogramEnumeration("GPU.ANGLE.D3D9InitializeResult",
                                                result.getID(), NUM_D3D9_INIT_ERRORS);
             }

src/libGLESv2/libGLESv2.def

@@ -286,3 +286,8 @@ EXPORTS
 
     ; Setting up TRACE macro callbacks
     SetTraceFunctionPointers        @284
+
+    ; ANGLE Platform Implementation
+    ANGLEPlatformCurrent            @290
+    ANGLEPlatformInitialize         @291
+    ANGLEPlatformShutdown           @292