This CL replaces current GUID generators (GetGenericSharedMemoryGUID-
-ForTracing and GetGpuMemoryBufferGUIDForTracing) with new GUID
generators GetSharedMemoryGUIDForTracing and GetGenericSharedGpumemory-
-GUIDForTracing. The formater is used for GPU memory buffer that use
base::SharedMemory, and the latter is not. This fix is required to know
shared memory usages on memory-infra accurately.

BUG=604726
TEST=n/a
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2819803002
Cr-Commit-Position: refs/heads/master@{#465529}