Make sure TextureManager is non-null before querying TextureRefs

GpuVideoDecodeAccelerator already handles the texture manager returning
null TextureRefs to support the passthrough command decoder. Now that
we skip allocating the TextureManager entirely, also protect against it
being null.

BUG=1059068

Change-Id: I2d1d2a3fbf8166002379724ab97eca5082621374
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2140674Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Commit-Queue: Frank Liberato <liberato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757445}

media/gpu/ipc/service/gpu_video_decode_accelerator.cc

@@ -466,42 +466,45 @@ void GpuVideoDecodeAccelerator::OnAssignPictureBuffers(
         return;
       }
 
-      gpu::gles2::TextureRef* texture_ref =
-          texture_manager->GetTexture(buffer_texture_ids[j]);
-      if (texture_ref) {
-        gpu::gles2::Texture* info = texture_ref->texture();
-        if (texture_target_ == GL_TEXTURE_EXTERNAL_OES ||
-            texture_target_ == GL_TEXTURE_RECTANGLE_ARB) {
-          // These textures have their dimensions defined by the underlying
-          // storage.
-          // Use |texture_dimensions_| for this size.
-          texture_manager->SetLevelInfo(texture_ref, texture_target_, 0,
-                                        GL_RGBA, texture_dimensions_.width(),
-                                        texture_dimensions_.height(), 1, 0,
-                                        GL_RGBA, GL_UNSIGNED_BYTE, gfx::Rect());
-        } else {
-          // For other targets, texture dimensions should already be defined.
-          GLsizei width = 0, height = 0;
-          info->GetLevelSize(texture_target_, 0, &width, &height, nullptr);
-          if (width != texture_dimensions_.width() ||
-              height != texture_dimensions_.height()) {
-            DLOG(ERROR) << "Size mismatch for texture id "
-                        << buffer_texture_ids[j];
-            NotifyError(VideoDecodeAccelerator::INVALID_ARGUMENT);
-            return;
-          }
-
-          // TODO(dshwang): after moving to D3D11, remove this.
-          // https://crbug.com/438691
-          GLenum format = video_decode_accelerator_->GetSurfaceInternalFormat();
-          if (format != GL_RGBA) {
-            DCHECK(format == GL_BGRA_EXT);
-            texture_manager->SetLevelInfo(texture_ref, texture_target_, 0,
-                                          format, width, height, 1, 0, format,
-                                          GL_UNSIGNED_BYTE, gfx::Rect());
+      if (texture_manager) {
+        gpu::gles2::TextureRef* texture_ref =
+            texture_manager->GetTexture(buffer_texture_ids[j]);
+        if (texture_ref) {
+          gpu::gles2::Texture* info = texture_ref->texture();
+          if (texture_target_ == GL_TEXTURE_EXTERNAL_OES ||
+              texture_target_ == GL_TEXTURE_RECTANGLE_ARB) {
+            // These textures have their dimensions defined by the underlying
+            // storage.
+            // Use |texture_dimensions_| for this size.
+            texture_manager->SetLevelInfo(
+                texture_ref, texture_target_, 0, GL_RGBA,
+                texture_dimensions_.width(), texture_dimensions_.height(), 1, 0,
+                GL_RGBA, GL_UNSIGNED_BYTE, gfx::Rect());
+          } else {
+            // For other targets, texture dimensions should already be defined.
+            GLsizei width = 0, height = 0;
+            info->GetLevelSize(texture_target_, 0, &width, &height, nullptr);
+            if (width != texture_dimensions_.width() ||
+                height != texture_dimensions_.height()) {
+              DLOG(ERROR) << "Size mismatch for texture id "
+                          << buffer_texture_ids[j];
+              NotifyError(VideoDecodeAccelerator::INVALID_ARGUMENT);
+              return;
+            }
+
+            // TODO(dshwang): after moving to D3D11, remove this.
+            // https://crbug.com/438691
+            GLenum format =
+                video_decode_accelerator_->GetSurfaceInternalFormat();
+            if (format != GL_RGBA) {
+              DCHECK(format == GL_BGRA_EXT);
+              texture_manager->SetLevelInfo(texture_ref, texture_target_, 0,
+                                            format, width, height, 1, 0, format,
+                                            GL_UNSIGNED_BYTE, gfx::Rect());
+            }
           }
+          current_textures.push_back(texture_ref);
         }
-        current_textures.push_back(texture_ref);
       }
       service_ids.push_back(texture_base->service_id());
     }