(This is a merge of http://go/wvgerrit/102104)
The device file unit tests use some custom matchers that were written
back when we didn't have C++11. Because gMock requires std::tuple to
pass a pointer AND a length to a matcher, these matchers had to estimate
the length of the file. This technically meant they were causing a
benign buffer overrun sometimes.
Since we have C++11 now, we can fix this by using a matcher over a
std::pair of the pointer and length. I also took the opportunity to
refactor the matchers a little. The old matchers had many very specific
overloads and also collided with the names of some standard gMock
matchers. Now there are just two more-general matchers with unique
names.
Test: CE CDM Unit Tests
Test: Android Unit Tests
Bug: 159463905
Change-Id: I758b140226bfe2bae6962ee5c64fd6af186b5819