Bug 1492580 - Limit glGetError flush loop and handle CONTEXT_LOST. r=lsalzman

Differential Revision: https://phabricator.services.mozilla.com/D11270

--HG--
extra : moz-landing-system : lando

gfx/gl/GLContext.cpp

@@ -2058,6 +2058,30 @@ GLContext::MarkDestroyed()
     mSymbols = {};
 }
 
+// -
+
+GLenum
+GLContext::RawGetErrorAndClear() const
+{
+    const GLenum ret = mSymbols.fGetError();
+
+    auto flushedErr = ret;
+    uint32_t i = 1;
+    while (flushedErr && flushedErr != LOCAL_GL_CONTEXT_LOST) {
+        if (i == 100) {
+            gfxCriticalError() << "Flushing glGetError still " << gfx::hexa(flushedErr)
+                               << " after " << i << " calls.";
+            break;
+        }
+        flushedErr = mSymbols.fGetError();
+        i += 1;
+    }
+
+    return ret;
+}
+
+// -
+
 #ifdef MOZ_GL_DEBUG
 /* static */ void
 GLContext::AssertNotPassingStackBufferToTheGL(const void* ptr)

gfx/gl/GLContext.h

@@ -579,18 +579,7 @@ public:
 private:
     mutable GLenum mTopError = 0;
 
-    GLenum RawGetError() const {
-        return mSymbols.fGetError();
-    }
-
-    GLenum RawGetErrorAndClear() const {
-        GLenum err = RawGetError();
-
-        if (err)
-            while (RawGetError()) {}
-
-        return err;
-    }
+    GLenum RawGetErrorAndClear() const;
 
     GLenum FlushErrors() const {
         GLenum err = RawGetErrorAndClear();