Capture/Replay: Add test to capture an uninitialized buffer

src/libANGLE/capture/frame_capture_utils.cpp

@@ -762,12 +762,19 @@ Result SerializeBuffer(const gl::Context *context,
 {
     GroupScope group(json, "Buffer");
     SerializeBufferState(json, buffer->getState());
-    MemoryBuffer *dataPtr = nullptr;
-    ANGLE_CHECK_GL_ALLOC(
-        const_cast<gl::Context *>(context),
-        scratchBuffer->getInitialized(static_cast<size_t>(buffer->getSize()), &dataPtr, 0));
-    ANGLE_TRY(buffer->getSubData(context, 0, dataPtr->size(), dataPtr->data()));
-    json->addBlob("data", dataPtr->data(), dataPtr->size());
+    if (buffer->getSize())
+    {
+        MemoryBuffer *dataPtr = nullptr;
+        ANGLE_CHECK_GL_ALLOC(
+            const_cast<gl::Context *>(context),
+            scratchBuffer->getInitialized(static_cast<size_t>(buffer->getSize()), &dataPtr, 0));
+        ANGLE_TRY(buffer->getSubData(context, 0, dataPtr->size(), dataPtr->data()));
+        json->addBlob("data", dataPtr->data(), dataPtr->size());
+    }
+    else
+    {
+        json->addCString("data", "null");
+    }
     return Result::Continue;
 }
 void SerializeColorGeneric(JsonSerializer *json,

src/tests/gl_tests/BufferDataTest.cpp

@@ -108,6 +108,16 @@ TEST_P(BufferDataTest, MAYBE_NULLData)
     }
 }
 
+// If glBufferData was not called yet the capturing must not try to
+// read the data. http://anglebug.com/6093
+TEST_P(BufferDataTest, Uninitialized)
+{
+    // Trigger frame capture to try capturing the
+    // generated but uninitialized buffer
+    glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
+    swapBuffers();
+}
+
 TEST_P(BufferDataTest, ZeroNonNULLData)
 {
     glBindBuffer(GL_ARRAY_BUFFER, mBuffer);