add range check to service-side MapBufferRange

gpu/command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc b/gpu/command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc
index fe14a776f3199ec8b472d8a75c9c28e776ce3a09..970860aa2cc612d47779fe608a214bce5213c672 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc
@@ -819,6 +819,9 @@ TEST_P(GLES3DecoderTest, ReadPixelsPixelPackBufferMapped) {
   GLint size = kWidth * kHeight * kBytesPerPixel;
 
   DoBindBuffer(GL_PIXEL_PACK_BUFFER, client_buffer_id_, kServiceBufferId);
+  DoBufferData(GL_PIXEL_PACK_BUFFER, size);
+
+  std::vector<int8_t> mapped_data(size);
 
   uint32_t result_shm_id = kSharedMemoryId;
   uint32_t result_shm_offset = kSharedMemoryOffset;
@@ -827,6 +830,7 @@ TEST_P(GLES3DecoderTest, ReadPixelsPixelPackBufferMapped) {
   uint32_t data_shm_offset = kSharedMemoryOffset + sizeof(uint32_t);
   EXPECT_CALL(*gl_,
               MapBufferRange(GL_PIXEL_PACK_BUFFER, 0, size, GL_MAP_READ_BIT))
+        .WillOnce(Return(mapped_data.data()))
         .RetiresOnSaturation();
   MapBufferRange map_buffer_range;
   map_buffer_range.Init(GL_PIXEL_PACK_BUFFER, 0, size, GL_MAP_READ_BIT,