Support ES 3.0 constants for bufferData's usage argument.

Source/modules/webgl/WebGLRenderingContextBase.cpp

Index: Source/modules/webgl/WebGLRenderingContextBase.cpp
diff --git a/Source/modules/webgl/WebGLRenderingContextBase.cpp b/Source/modules/webgl/WebGLRenderingContextBase.cpp
index 4e53c20f450f360fc3c6306714410d5e20994055..22cfe6a599191491d06b66479de3dc641ee58cd0 100644
--- a/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -1569,15 +1569,8 @@ void WebGLRenderingContextBase::bufferDataImpl(GLenum target, long long size, co
     if (!buffer)
         return;
 
-    switch (usage) {
-    case GL_STREAM_DRAW:
-    case GL_STATIC_DRAW:
-    case GL_DYNAMIC_DRAW:
-        break;
-    default:
-        synthesizeGLError(GL_INVALID_ENUM, "bufferData", "invalid usage");
+    if (!validateBufferDataUsage("bufferData", usage))
         return;
-    }
 
     if (!validateValueFitNonNegInt32("bufferData", "size", size))
         return;
@@ -6130,6 +6123,19 @@ WebGLBuffer* WebGLRenderingContextBase::validateBufferDataTarget(const char* fun
     return buffer;
 }
 
+bool WebGLRenderingContextBase::validateBufferDataUsage(const char* functionName, GLenum usage)
+{
+    switch (usage) {
+    case GL_STREAM_DRAW:
+    case GL_STATIC_DRAW:
+    case GL_DYNAMIC_DRAW:
+        return true;
+    default:
+        synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid usage");
+        return false;
+    }
+}
+
 void WebGLRenderingContextBase::removeBoundBuffer(WebGLBuffer* buffer)
 {
     if (m_boundArrayBuffer == buffer)