Add InitializationStateDcheck, its base class, and their tests

Add InitializationStateDcheck, its base class, and their tests.

TEST=util_test InitializationState*
R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/21af17394033

[Robert Sesek, 2014-08-13 20:13:37]

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
File util/misc/initialization_state.h (right):

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
util/misc/initialization_state.h:38: enum State : uint8_t {
Is this necessary? Won't the compiler choose the best-fit type?

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
util/misc/initialization_state.h:87: State state_;
DISALLOW_COPY_AND_ASSIGN

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
File util/misc/initialization_state_dcheck.h (right):

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
util/misc/initialization_state_dcheck.h:83: //! returns the object’s current
state.
It seems like it should be illegal to call Begin() twice.

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
util/misc/initialization_state_dcheck.h:87: State Begin();
private:
 DISALLLOW_COPY_AND_ASSIGN() ?

[Mark Mentovai, 2014-08-13 22:22:06]

I also changed this to require that a transition into the valid state can only
come from the invalid (initializing) state.

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
File util/misc/initialization_state.h (right):

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
util/misc/initialization_state.h:38: enum State : uint8_t {
rsesek wrote:
> Is this necessary? Won't the compiler choose the best-fit type?

Not “best” fit, no. clang and gcc would choose int for this enum if you didn’t
hold their hands.

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
File util/misc/initialization_state_dcheck.h (right):

https://codereview.chromium.org/465103002/diff/20001/util/misc/initialization...
util/misc/initialization_state_dcheck.h:83: //! returns the object’s current
state.
rsesek wrote:
> It seems like it should be illegal to call Begin() twice.

It’s illegal to call Begin() at all without doing it through the macro, and it’s
illegal to call it through that macro twice. The Invalid_NotUninitialized test
makes sure of it.

[Robert Sesek, 2014-08-14 16:14:19]

LGTM

[Mark Mentovai, 2014-08-14 16:51:31]

Committed patchset #5 manually as 21af17394033 (presubmit successful).