Use implicit_cast<> instead of static_cast<> whenever possible

Use implicit_cast<> instead of static_cast<> whenever possible.

implicit_cast<> only performs a cast in cases where an implicit
conversion would be possible. It’s even safer than static_cast<> It’s an
“explicit implicit” cast, which is not normally necsesary, but is
frequently required when working with the ?: operator, functions like
std::min() and std::max(), and logging and testing macros.

The public style guide does not mention implicit_cast<> only because it
is not part of the standard library, but would otherwise require it in
these situations. Since base does provide implicit_cast<>, it should be
used whenever possible.

The only uses of static_cast<> not converted to implicit_cast<> are
those that require static_cast<>, such as those that assign an integer
constant to a variable of an enum type.

R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/48b1964d1b215dae805bdf08089007bb8a7b285f

[Mark Mentovai, 2014-11-06 14:45:22]

mark@chromium.org changed reviewers:
+ rsesek@chromium.org

[Robert Sesek, 2014-11-06 19:52:26]

LGTM

https://codereview.chromium.org/700383007/diff/1/client/simple_string_diction...
File client/simple_string_dictionary.h (right):

https://codereview.chromium.org/700383007/diff/1/client/simple_string_diction...
client/simple_string_dictionary.h:234: DCHECK_EQ(GetEntryForKey(key),
implicit_cast<Entry*>(nullptr));
Is this cast necessary with nullptr?

[Mark Mentovai, 2014-11-06 21:44:35]

https://codereview.chromium.org/700383007/diff/1/client/simple_string_diction...
File client/simple_string_dictionary.h (right):

https://codereview.chromium.org/700383007/diff/1/client/simple_string_diction...
client/simple_string_dictionary.h:234: DCHECK_EQ(GetEntryForKey(key),
implicit_cast<Entry*>(nullptr));
Robert Sesek wrote:
> Is this cast necessary with nullptr?

Unfortunately, it still is.

[Mark Mentovai, 2014-11-06 21:44:49]

Committed patchset #1 (id:1) manually as
48b1964d1b215dae805bdf08089007bb8a7b285f (presubmit successful).