Fix double lock of texture resource in software renderer

cc/output/gl_renderer.cc

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/gl_renderer.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <string>
@@ skipping 2694 matching lines @@
   } else {
     SetStencilEnabled(false);
   }
 }
 
 bool GLRenderer::BindFramebufferToTexture(DrawingFrame* frame,
                                           const ScopedResource* texture,
                                           const gfx::Rect& target_rect) {
   DCHECK(texture->id());
 
+  // Explicitly release lock, otherwise we can crash when try to lock
+  // same texture again.
   current_framebuffer_lock_ = nullptr;
 
   SetStencilEnabled(false);
   GLC(gl_, gl_->BindFramebuffer(GL_FRAMEBUFFER, offscreen_framebuffer_id_));
   current_framebuffer_lock_ =
       make_scoped_ptr(new ResourceProvider::ScopedWriteLockGL(
           resource_provider_, texture->id()));
   unsigned texture_id = current_framebuffer_lock_->texture_id();
   GLC(gl_,
       gl_->FramebufferTexture2D(
@@ skipping 581 matching lines @@
     context_support_->ScheduleOverlayPlane(
         overlay.plane_z_order,
         overlay.transform,
         pending_overlay_resources_.back()->texture_id(),
         overlay.display_rect,
         overlay.uv_rect);
   }
 }
 
 }  // namespace cc