aw: Avoid leaking GL error across android and chromium

android_webview/browser/scoped_app_gl_state_restore.cc

Index: android_webview/browser/scoped_app_gl_state_restore.cc
diff --git a/android_webview/browser/scoped_app_gl_state_restore.cc b/android_webview/browser/scoped_app_gl_state_restore.cc
index 71a5711a26f7967fdbef4830738e810a673b98c3..1f948d254cd38f668e50d89cda89c3a598789c6d 100644
--- a/android_webview/browser/scoped_app_gl_state_restore.cc
+++ b/android_webview/browser/scoped_app_gl_state_restore.cc
@@ -148,6 +148,11 @@ ScopedAppGLStateRestoreImpl::ScopedAppGLStateRestoreImpl(
   TRACE_EVENT0("android_webview", "AppGLStateSave");
   MakeAppContextCurrent();
 
+  // Ignore incoming GL errors.
+  GLenum error = glGetError();
+  DLOG_IF(WARNING, error != static_cast<GLenum>(GL_NO_ERROR))
+      << "Incoming GLError " << error;

[no sievers, 2014/05/15 20:49:24]

Since it's an error stack you need to loop over it, see
ErrorStateImpl::ClearRealGLErrors() in error_state.cc

+
   if (!g_globals_initialized) {
     g_globals_initialized = true;
 
@@ -251,12 +256,15 @@ ScopedAppGLStateRestoreImpl::ScopedAppGLStateRestoreImpl(
     glGetVertexAttribfv(
         i, GL_CURRENT_VERTEX_ATTRIB, vertex_attrib_[i].current_vertex_attrib);
   }
+  DCHECK_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR));
 }
 
 ScopedAppGLStateRestoreImpl::~ScopedAppGLStateRestoreImpl() {
   TRACE_EVENT0("android_webview", "AppGLStateRestore");
   MakeAppContextCurrent();
 
+  DCHECK_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR));
+
   glBindFramebufferEXT(GL_FRAMEBUFFER, framebuffer_binding_ext_);
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_array_buffer_binding_);
 
@@ -347,6 +355,11 @@ ScopedAppGLStateRestoreImpl::~ScopedAppGLStateRestoreImpl() {
 
   GLEnableDisable(GL_STENCIL_TEST, stencil_test_);
   glStencilFunc(stencil_func_, stencil_mask_, stencil_ref_);
+
+  // Do not leak GLError out of chromium.
+  GLenum error = glGetError();
+  DLOG_IF(WARNING, error != static_cast<GLenum>(GL_NO_ERROR))
+      << "Chromium produced GLError " << error;
 }
 
 }  // namespace internal