Support Simple Cache in disk_cache_perftest.

Support Simple Cache in disk_cache_perftest.

I need to validate improvements to Simple Cache for Mac/Windows, this
perftest is a great start. First, let's make the existing behaviour
work for both cache backends.

R=juliatuttle@chromium.org
BUG=611464
Committed: https://crrev.com/c28fe1128c07709a72f0f06e52ef31612b2f2ab3
Cr-Commit-Position: refs/heads/master@{#393572}

[gavinp, 2016-05-12 17:46:13]

Julia: PTAL.

Do these build in any of the tries? I'm a bit anxious about if directory
flushing works on all platforms.

Interesting note: the simple cache is brutally slow with a cold cache on the
existing test. Sample results on Linux:

[==========] Running 4 tests from 1 test case.                                  
                                                                                
                                             
[----------] Global test environment set-up.                                    
                                                                                
                                             
[----------] 4 tests from DiskCachePerfTest                                     
                                                                                
                                             
[ RUN      ] DiskCachePerfTest.Hash                                             
                                                                                
                                             
Hash disk cache keys    1001.78 ms                                              
                                                                                
                                             
[       OK ] DiskCachePerfTest.Hash (1002 ms)                                   
                                                                                
                                             
[ RUN      ] DiskCachePerfTest.CacheBackendPerformance                          
                                                                                
                                             
Write disk cache entries        499.857 ms                                      
                                                                                
                                             
Read disk cache entries (cold)  825.359 ms                                      
                                                                                
                                             
Read disk cache entries (warm)  818.468 ms                                      
                                                                                
                                             
[       OK ] DiskCachePerfTest.CacheBackendPerformance (3008 ms)                
                                                                                
                                             
[ RUN      ] DiskCachePerfTest.SimpleCacheBackendPerformance                    
                                                                                
                                             
Write disk cache entries        327.344 ms                                      
                                                                                
                                             
Read disk cache entries (cold)  4233.94 ms                                      
                                                                                
                                             
Read disk cache entries (warm)  784.5   ms                                      
                                                                                
                                             
[       OK ] DiskCachePerfTest.SimpleCacheBackendPerformance (38152 ms)         
                                                                                
                                             
[ RUN      ] DiskCachePerfTest.BlockFilesPerformance                            
                                                                                
                                             
Fill three block-files  215.103 ms                                              
                                                                                
                                             
Create and delete blocks        1308.21 ms                                      
                                                                                
                                             
[       OK ] DiskCachePerfTest.BlockFilesPerformance (1526 ms)                  
                                                                                
                                             
[----------] 4 tests from DiskCachePerfTest (43688 ms total)                    
                                                                                
                                             
                                                                                
                                                                                
                                             
[----------] Global test environment tear-down                                  
                                                                                
                                             
[==========] 4 tests from 1 test case ran. (43688 ms total)                     
                                                                                
                                             
[  PASSED  ] 4 tests.

[Julia Tuttle, 2016-05-13 16:25:53]

lgtm, and looks like it looks good to the trybots too (at least patch set 2).

[gavinp, 2016-05-13 16:50:25]

The CQ bit was checked by gavinp@chromium.org

[commit-bot: I haz the power, 2016-05-13 16:50:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1969413003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1969413003/40001

[commit-bot: I haz the power, 2016-05-13 17:49:17]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-05-13 17:51:31]

Description was changed from

==========
Support Simple Cache in disk_cache_perftest.

I need to validate improvements to Simple Cache for Mac/Windows, this
perftest is a great start. First, let's make the existing behaviour
work for both cache backends.

R=juliatuttle@chromium.org
BUG=611464
==========

to

==========
Support Simple Cache in disk_cache_perftest.

I need to validate improvements to Simple Cache for Mac/Windows, this
perftest is a great start. First, let's make the existing behaviour
work for both cache backends.

R=juliatuttle@chromium.org
BUG=611464

Committed: https://crrev.com/c28fe1128c07709a72f0f06e52ef31612b2f2ab3
Cr-Commit-Position: refs/heads/master@{#393572}
==========

[commit-bot: I haz the power, 2016-05-13 17:51:31]

Patchset 3 (id:??) landed as
https://crrev.com/c28fe1128c07709a72f0f06e52ef31612b2f2ab3
Cr-Commit-Position: refs/heads/master@{#393572}