Unbreak ppapi_example_video_decode for platforms that don't have ARB extensions.

ppapi/examples/video_decode/video_decode.cc

Index: ppapi/examples/video_decode/video_decode.cc
diff --git a/ppapi/examples/video_decode/video_decode.cc b/ppapi/examples/video_decode/video_decode.cc
index 4e3354ae2bd9986472c2e99a3fadf1c5c3e01c66..affea3cc25c0dee4d5035ccee64c68a07875f7b1 100644
--- a/ppapi/examples/video_decode/video_decode.cc
+++ b/ppapi/examples/video_decode/video_decode.cc
@@ -135,6 +135,8 @@ class VideoDecodeDemoInstance : public pp::Instance,
   void InitGL();
   GLuint CreateTexture(int32_t width, int32_t height, GLenum texture_target);
   void CreateGLObjects();
+  void Create2DProgramOnce();
+  void CreateRectangleARBProgramOnce();
   Shader CreateProgram(const char* vertex_shader,
                        const char* fragment_shader);
   void CreateShader(GLuint program, GLenum type, const char* source, int size);
@@ -424,11 +426,13 @@ void VideoDecodeDemoInstance::PictureReady(PP_Resource decoder,
   }
 
   if (info.texture_target == GL_TEXTURE_2D) {
+    Create2DProgramOnce();
     gles2_if_->UseProgram(context_->pp_resource(), shader_2d_.program);
     gles2_if_->Uniform2f(
         context_->pp_resource(), shader_2d_.texcoord_scale_location, 1.0, 1.0);
   } else {
     assert(info.texture_target == GL_TEXTURE_RECTANGLE_ARB);
+    CreateRectangleARBProgramOnce();
     gles2_if_->UseProgram(
         context_->pp_resource(), shader_rectangle_arb_.program);
     gles2_if_->Uniform2f(context_->pp_resource(),
@@ -564,18 +568,36 @@ void VideoDecodeDemoInstance::DeleteTexture(GLuint id) {
 }
 
 void VideoDecodeDemoInstance::CreateGLObjects() {
-  // Code and constants for shader.
-  static const char kVertexShader[] =
-      "varying vec2 v_texCoord;            \n"
-      "attribute vec4 a_position;          \n"
-      "attribute vec2 a_texCoord;          \n"
-      "uniform vec2 v_scale;               \n"
-      "void main()                         \n"
-      "{                                   \n"
-      "    v_texCoord = v_scale * a_texCoord; \n"
-      "    gl_Position = a_position;       \n"
-      "}";
+  // Assign vertex positions and texture coordinates to buffers for use in
+  // shader program.
+  static const float kVertices[] = {
+    -1, 1, -1, -1, 1, 1, 1, -1,  // Position coordinates.
+    0, 1, 0, 0, 1, 1, 1, 0,      // Texture coordinates.
+  };
 
+  GLuint buffer;
+  gles2_if_->GenBuffers(context_->pp_resource(), 1, &buffer);
+  gles2_if_->BindBuffer(context_->pp_resource(), GL_ARRAY_BUFFER, buffer);
+
+  gles2_if_->BufferData(context_->pp_resource(), GL_ARRAY_BUFFER,
+                        sizeof(kVertices), kVertices, GL_STATIC_DRAW);
+  assertNoGLError();
+}
+
+static const char kVertexShader[] =
+    "varying vec2 v_texCoord;            \n"
+    "attribute vec4 a_position;          \n"
+    "attribute vec2 a_texCoord;          \n"
+    "uniform vec2 v_scale;               \n"
+    "void main()                         \n"
+    "{                                   \n"
+    "    v_texCoord = v_scale * a_texCoord; \n"
+    "    gl_Position = a_position;       \n"
+    "}";
+
+void VideoDecodeDemoInstance::Create2DProgramOnce() {
+  if (shader_2d_.program)
+    return;
   static const char kFragmentShader2D[] =
       "precision mediump float;            \n"
       "varying vec2 v_texCoord;            \n"
@@ -584,7 +606,13 @@ void VideoDecodeDemoInstance::CreateGLObjects() {
       "{"
       "    gl_FragColor = texture2D(s_texture, v_texCoord); \n"
       "}";
+  shader_2d_ = CreateProgram(kVertexShader, kFragmentShader2D);
+  assertNoGLError();
+}
 
+void VideoDecodeDemoInstance::CreateRectangleARBProgramOnce() {
+  if (shader_rectangle_arb_.program)
+    return;
   static const char kFragmentShaderRectangle[] =
       "#extension GL_ARB_texture_rectangle : require\n"
       "precision mediump float;            \n"
@@ -594,23 +622,6 @@ void VideoDecodeDemoInstance::CreateGLObjects() {
       "{"
       "    gl_FragColor = texture2DRect(s_texture, v_texCoord).rgba; \n"
       "}";
-
-  // Assign vertex positions and texture coordinates to buffers for use in
-  // shader program.
-  static const float kVertices[] = {
-    -1, 1, -1, -1, 1, 1, 1, -1,  // Position coordinates.
-    0, 1, 0, 0, 1, 1, 1, 0,      // Texture coordinates.
-  };
-
-  GLuint buffer;
-  gles2_if_->GenBuffers(context_->pp_resource(), 1, &buffer);
-  gles2_if_->BindBuffer(context_->pp_resource(), GL_ARRAY_BUFFER, buffer);
-
-  gles2_if_->BufferData(context_->pp_resource(), GL_ARRAY_BUFFER,
-                        sizeof(kVertices), kVertices, GL_STATIC_DRAW);
-  assertNoGLError();
-
-  shader_2d_ = CreateProgram(kVertexShader, kFragmentShader2D);
   shader_rectangle_arb_ =
       CreateProgram(kVertexShader, kFragmentShaderRectangle);
 }