Make CreateAndConsumeTexture always associate client_id with a service_id

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index d1d1d9ce97e67a92688eff24a752e9cb06fd542a..4652c38b229ddf58da8775ee4f000c6e17c6b47f 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -967,6 +967,7 @@ class GLES2DecoderImpl : public GLES2Decoder,
   void ProduceTextureRef(std::string func_name, TextureRef* texture_ref,
       GLenum target, const GLbyte* data);
 
+  void EnsureTextureForClientId(GLuint client_id);
   void DoConsumeTextureCHROMIUM(GLenum target, const GLbyte* key);
   void DoCreateAndConsumeTextureCHROMIUM(GLenum target, const GLbyte* key,
     GLuint client_id);
@@ -11679,6 +11680,19 @@ void GLES2DecoderImpl::DoConsumeTextureCHROMIUM(GLenum target,
   }
 }
 
+void GLES2DecoderImpl::EnsureTextureForClientId(GLuint client_id) {
+  TextureRef* texture_ref = GetTexture(client_id);
+  if (!texture_ref) {
+    GLuint service_id;
+    glGenTextures(1, &service_id);
+    DCHECK_NE(0u, service_id);
+    CreateTexture(client_id, service_id);

[piman, 2015/04/03 18:17:14]

I think we also want to do the texture_manager()->SetTarget(texture_ref,
target); (that would be done in BindTexture), to make sure the texture would
have the right target.

Actually, I think we would also want to do the actual glBindTexture to create
the texture on the GL side, but then restore the currently bound texture
(because there shouldn't be the side effect on the context)

It matters in very subtle ways (e.g. if someone tries to bind the texture to a
framebuffer object).

+  }
+}
+
+// If CreateAndConsumeTexture fails we still need to ensure that the client_id
+// provided is associated with a service_id/TextureRef for consistency, even if
+// the resulting texture is incomplete.
 error::Error GLES2DecoderImpl::HandleCreateAndConsumeTextureCHROMIUMImmediate(
     uint32_t immediate_data_size,
     const void* cmd_data) {
@@ -11687,24 +11701,28 @@ error::Error GLES2DecoderImpl::HandleCreateAndConsumeTextureCHROMIUMImmediate(
           const gles2::cmds::CreateAndConsumeTextureCHROMIUMImmediate*>(
           cmd_data);
   GLenum target = static_cast<GLenum>(c.target);
+  uint32_t client_id = c.client_id;
   uint32_t data_size;
   if (!ComputeDataSize(1, sizeof(GLbyte), 64, &data_size)) {
+    EnsureTextureForClientId(client_id);

[piman, 2015/04/03 18:17:14]

I think it's ok to skip here. We're losing the context anyway (this is what
would happen in the !immediate version).

     return error::kOutOfBounds;
   }
   if (data_size > immediate_data_size) {
+    EnsureTextureForClientId(client_id);

[piman, 2015/04/03 18:17:15]

Here too.

     return error::kOutOfBounds;
   }
   const GLbyte* mailbox =
       GetImmediateDataAs<const GLbyte*>(c, data_size, immediate_data_size);
   if (!validators_->texture_bind_target.IsValid(target)) {
+    EnsureTextureForClientId(client_id);

[piman, 2015/04/03 18:17:14]

Here too. Because we don't have a valid target, after the suggested change to
EnsureTextureForClientId, we wouldn't be able to SetTarget/glBindTexture anyway.

     LOCAL_SET_GL_ERROR_INVALID_ENUM(
         "glCreateAndConsumeTextureCHROMIUM", target, "target");
     return error::kNoError;
   }
   if (mailbox == NULL) {
+    EnsureTextureForClientId(client_id);

[piman, 2015/04/03 18:17:14]

Here too.

     return error::kOutOfBounds;
   }
-  uint32_t client_id = c.client_id;
   DoCreateAndConsumeTextureCHROMIUM(target, mailbox, client_id);
   return error::kNoError;
 }
@@ -11721,6 +11739,8 @@ void GLES2DecoderImpl::DoCreateAndConsumeTextureCHROMIUM(GLenum target,
 
   TextureRef* texture_ref = GetTexture(client_id);
   if (texture_ref) {
+    // No need to call EnsureTextureForClientId here, the client_id already has
+    // an associated texture.
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         "glCreateAndConsumeTextureCHROMIUM", "client id already in use");
@@ -11728,12 +11748,15 @@ void GLES2DecoderImpl::DoCreateAndConsumeTextureCHROMIUM(GLenum target,
   }
   Texture* texture = group_->mailbox_manager()->ConsumeTexture(mailbox);
   if (!texture) {
+    EnsureTextureForClientId(client_id);
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         "glCreateAndConsumeTextureCHROMIUM", "invalid mailbox name");
     return;
   }
+
   if (texture->target() != target) {
+    EnsureTextureForClientId(client_id);
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         "glCreateAndConsumeTextureCHROMIUM", "invalid target");