Skip ElfCoreDumpTest.ValidCoreFile test if no core dump is generated.

Skip ElfCoreDumpTest.ValidCoreFile test if no core dump is generated.

CrashGenerator::CreateChildCrash() may have some flakiness. This patch
changes ElfCoreDumpTest to temporarily skip the ValidCoreFile test if
no core dump is generated by CrashGenerator::CreateChildCrash(), but
print out the error message to help debug the flakiness.

BUG=chromium-os:24982
TEST=Tested the following:
1. Build on 32-bit and 64-bit Linux with gcc 4.6.
2. All unit tests pass.

[Lei Zhang (chromium)]

http://breakpad.appspot.com/342001/diff/1/2
File src/common/linux/elf_core_dump_unittest.cc (right):

http://breakpad.appspot.com/342001/diff/1/2#newcode185
Line 185: #if defined(__i386) || defined(__x86_64)
Are these changes suppose to be part of this CL?

[Ben Chan]

http://breakpad.appspot.com/342001/diff/1/2
File src/common/linux/elf_core_dump_unittest.cc (right):

http://breakpad.appspot.com/342001/diff/1/2#newcode185
Line 185: #if defined(__i386) || defined(__x86_64)
On 2012/01/11 22:13:17, thestig wrote:
> Are these changes suppose to be part of this CL?

I noticed some compiler warnings about unused variables, so I made these
changes. But I can remove them if they seem unrelated.

[Ben Chan]

http://breakpad.appspot.com/342001/diff/1/2
File src/common/linux/elf_core_dump_unittest.cc (right):

http://breakpad.appspot.com/342001/diff/1/2#newcode185
Line 185: #if defined(__i386) || defined(__x86_64)
On 2012/01/11 22:16:04, Ben Chan wrote:
> On 2012/01/11 22:13:17, thestig wrote:
> > Are these changes suppose to be part of this CL?
> 
> I noticed some compiler warnings about unused variables, so I made these
> changes. But I can remove them if they seem unrelated.

Removed. Will fix them in another CL.

[Lei Zhang (chromium)]

LGTM