Add gl null driver tests to DrawElements.

src/libANGLE/renderer/gl/BufferGL.cpp

@@ -216,9 +216,17 @@ angle::Result BufferGL::getIndexRange(const gl::Context *context,
         const uint8_t *bufferData =
             MapBufferRangeWithFallback(mFunctions, gl::ToGLenum(DestBufferOperationTarget), offset,
                                        count * typeBytes, GL_MAP_READ_BIT);
+        if (bufferData)
+        {
             *outRange = gl::ComputeIndexRange(type, bufferData, count, primitiveRestartEnabled);
             mFunctions->unmapBuffer(gl::ToGLenum(DestBufferOperationTarget));
         }
+        else
+        {
+            // Workaround the null driver not having map support.
+            *outRange = gl::IndexRange(0, 0, 1);
+        }
+    }
 
     return angle::Result::Continue;
 }

src/libANGLE/renderer/gl/renderergl_utils.cpp

@@ -413,6 +413,12 @@ void GenerateCaps(const FunctionsGL *functions,
         functions->isAtLeastGLES(gl::Version(3, 0)))
     {
         caps->maxElementIndex = QuerySingleGLInt64(functions, GL_MAX_ELEMENT_INDEX);
+
+        // Work around the null driver limitations.
+        if (caps->maxElementIndex == 0)
+        {
+            caps->maxElementIndex = 0xFFFF;
+        }
     }
     else
     {

src/tests/perf_tests/DrawElementsPerf.cpp

@@ -232,10 +232,12 @@ DrawElementsPerfParams DrawElementsPerfD3D9Params(bool indexBufferChanged)
     return params;
 }
 
-DrawElementsPerfParams DrawElementsPerfOpenGLOrGLESParams(bool indexBufferChanged, GLenum indexType)
+DrawElementsPerfParams DrawElementsPerfOpenGLOrGLESParams(bool indexBufferChanged,
+                                                          bool useNullDevice,
+                                                          GLenum indexType)
 {
     DrawElementsPerfParams params;
-    params.eglParameters      = angle::egl_platform::OPENGL_OR_GLES(false);
+    params.eglParameters      = angle::egl_platform::OPENGL_OR_GLES(useNullDevice);
     params.indexBufferChanged = indexBufferChanged;
     params.type               = indexType;
 
@@ -277,10 +279,11 @@ ANGLE_INSTANTIATE_TEST(DrawElementsPerfBenchmark,
                        DrawElementsPerfD3D11Params(true, false, GL_UNSIGNED_INT),
                        DrawElementsPerfD3D11Params(false, false, GL_UNSIGNED_SHORT),
                        DrawElementsPerfD3D11Params(false, true, GL_UNSIGNED_SHORT),
-                       DrawElementsPerfOpenGLOrGLESParams(false, GL_UNSIGNED_SHORT),
-                       DrawElementsPerfOpenGLOrGLESParams(true, GL_UNSIGNED_SHORT),
-                       DrawElementsPerfOpenGLOrGLESParams(false, GL_UNSIGNED_INT),
-                       DrawElementsPerfOpenGLOrGLESParams(true, GL_UNSIGNED_INT),
+                       DrawElementsPerfOpenGLOrGLESParams(false, false, GL_UNSIGNED_SHORT),
+                       DrawElementsPerfOpenGLOrGLESParams(false, true, GL_UNSIGNED_SHORT),
+                       DrawElementsPerfOpenGLOrGLESParams(true, false, GL_UNSIGNED_SHORT),
+                       DrawElementsPerfOpenGLOrGLESParams(false, false, GL_UNSIGNED_INT),
+                       DrawElementsPerfOpenGLOrGLESParams(true, false, GL_UNSIGNED_INT),
                        DrawElementsPerfVulkanParams(false, false, GL_UNSIGNED_SHORT),
                        DrawElementsPerfVulkanParams(false, true, GL_UNSIGNED_SHORT),
                        DrawElementsPerfVulkanParams(false, false, GL_UNSIGNED_INT),