Revert of SkThreadPool ~~> SkTaskGroup (patchset #4 id:60001 of https://codereview.chromium.org/531653002/)

Reason for revert:
Leaks, leaks, leaks.

Original issue's description:
> SkThreadPool ~~> SkTaskGroup
>
> SkTaskGroup is like SkThreadPool except the threads stay in
> one global pool.  Each SkTaskGroup itself is tiny (4 bytes)
> and its wait() method applies only to tasks add()ed to that
> instance, not the whole thread pool.
>
> This means we don't need to bring up new thread pools when
> tests themselves want to use multithreading (e.g. pathops,
> quilt).  We just create a new SkTaskGroup and wait for that
> to complete.  This should be more efficient, and allow us
> to expand where we use threads to really latency sensitive
> places.  E.g. we can probably now use these in nanobench
> for CPU .skp rendering.
>
> Now that all threads are sharing the same pool, I think we
> can remove most of the custom mechanism pathops tests use
> to control threading.  They'll just ride on the global pool
> with all other tests now.
>
> This (temporarily?) removes the GPU multithreading feature
> from DM, which we don't use.
>
> On my desktop, DM runs a little faster (57s -> 55s) in
> Debug, and a lot faster in Release (36s -> 24s).  The bots
> show speedups of similar proportions, cutting more than a
> minute off the N4/Release and Win7/Debug runtimes.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/9c7207b5dc71dc5a96a2eb107d401133333d5b6f

R=caryclark@google.com, bsalomon@google.com, bungeman@google.com, reed@google.com, mtklein@chromium.org
TBR=bsalomon@google.com, bungeman@google.com, caryclark@google.com, mtklein@chromium.org, reed@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Author: mtklein@google.com

Review URL: https://codereview.chromium.org/533393002

5 files changed, 18 insertions, 17 deletions

diff --git a/tools/flags/SkCommonFlags.cpp b/tools/flags/SkCommonFlags.cpp
index 7776c36a59..4d08ba6340 100644
--- a/tools/flags/SkCommonFlags.cpp
+++ b/tools/flags/SkCommonFlags.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "SkCommonFlags.h"
+#include "SkThreadPool.h"
 
 DEFINE_string(config, "565 8888 pdf gpu nonrendering angle",
               "Options: 565 8888 pdf gpu nonrendering msaa4 msaa16 nvprmsaa4 nvprmsaa16 "
@@ -41,10 +42,12 @@ DEFINE_bool(resetGpuContext, true, "Reset the GrContext before running each test
 DEFINE_bool(abandonGpuContext, false, "Abandon the GrContext after running each test. "
                                       "Implies --resetGpuContext.");
 
+DEFINE_bool2(single, z, false, "run tests on a single thread internally.");
+
 DEFINE_string(skps, "skps", "Directory to read skps from.");
 
-DEFINE_int32(threads, 0, "Run threadsafe tests on a threadpool with this many threads, "
-                         "defaulting to one thread per core.");
+DEFINE_int32(threads, SkThreadPool::kThreadPerCore,
+             "run threadsafe tests on a threadpool with this many threads.");
 
 DEFINE_bool2(verbose, v, false, "enable verbose output from the test driver.");
 
diff --git a/tools/flags/SkCommonFlags.h b/tools/flags/SkCommonFlags.h
index ecd4148448..b45ef0738a 100644
--- a/tools/flags/SkCommonFlags.h
+++ b/tools/flags/SkCommonFlags.h
@@ -20,6 +20,7 @@ DECLARE_string(match);
 DECLARE_bool(quiet);
 DECLARE_bool(resetGpuContext);
 DECLARE_bool(abandonGpuContext);
+DECLARE_bool(single);
 DECLARE_string(skps);
 DECLARE_int32(threads);
 DECLARE_string(resourcePath);
diff --git a/tools/iOSShell.cpp b/tools/iOSShell.cpp
index 8656e645aa..49be34d65b 100644
--- a/tools/iOSShell.cpp
+++ b/tools/iOSShell.cpp
@@ -12,6 +12,7 @@
 #include "SkCanvas.h"
 #include "SkCommonFlags.h"
 #include "SkGraphics.h"
+#include "SkThreadPool.h"
 #include "SkWindow.h"
 #include "sk_tool_utils.h"
 
diff --git a/tools/skpdiff/SkDiffContext.cpp b/tools/skpdiff/SkDiffContext.cpp
index 78d8400968..42d20de19d 100644
--- a/tools/skpdiff/SkDiffContext.cpp
+++ b/tools/skpdiff/SkDiffContext.cpp
@@ -12,7 +12,7 @@
 #include "SkSize.h"
 #include "SkStream.h"
 #include "SkTDict.h"
-#include "SkTaskGroup.h"
+#include "SkThreadPool.h"
 
 // from the tools directory for replace_char(...)
 #include "picture_utils.h"
@@ -24,6 +24,7 @@
 SkDiffContext::SkDiffContext() {
     fDiffers = NULL;
     fDifferCount = 0;
+    fThreadCount = SkThreadPool::kThreadPerCore;
 }
 
 SkDiffContext::~SkDiffContext() {
@@ -86,7 +87,7 @@ static SkString get_common_prefix(const SkString& a, const SkString& b) {
 }
 
 static SkString get_combined_name(const SkString& a, const SkString& b) {
-    // Note (stephana): We must keep this function in sync with
+    // Note (stephana): We must keep this function in sync with 
     // getImageDiffRelativeUrl() in static/loader.js (under rebaseline_server).
     SkString result = a;
     result.append("-vs-");
@@ -237,7 +238,7 @@ void SkDiffContext::diffDirectories(const char baselinePath[], const char testPa
         return;
     }
 
-    SkTaskGroup tg;
+    SkThreadPool threadPool(fThreadCount);
     SkTArray<SkThreadedDiff> runnableDiffs;
     runnableDiffs.reset(baselineEntries.count());
 
@@ -252,11 +253,13 @@ void SkDiffContext::diffDirectories(const char baselinePath[], const char testPa
         if (sk_exists(testFile.c_str()) && !sk_isdir(testFile.c_str())) {
             // Queue up the comparison with the differ
             runnableDiffs[x].setup(this, baselineFile, testFile);
-            tg.add(&runnableDiffs[x]);
+            threadPool.add(&runnableDiffs[x]);
         } else {
             SkDebugf("Baseline file \"%s\" has no corresponding test file\n", baselineFile.c_str());
         }
     }
+
+    threadPool.wait();
 }
 
 
@@ -281,14 +284,16 @@ void SkDiffContext::diffPatterns(const char baselinePattern[], const char testPa
         return;
     }
 
-    SkTaskGroup tg;
+    SkThreadPool threadPool(fThreadCount);
     SkTArray<SkThreadedDiff> runnableDiffs;
     runnableDiffs.reset(baselineEntries.count());
 
     for (int x = 0; x < baselineEntries.count(); x++) {
         runnableDiffs[x].setup(this, baselineEntries[x], testEntries[x]);
-        tg.add(&runnableDiffs[x]);
+        threadPool.add(&runnableDiffs[x]);
     }
+
+    threadPool.wait();
 }
 
 void SkDiffContext::outputRecords(SkWStream& stream, bool useJSONP) {
diff --git a/tools/valgrind.supp b/tools/valgrind.supp
index f0331ed4cb..d96ada04e7 100644
--- a/tools/valgrind.supp
+++ b/tools/valgrind.supp
@@ -213,12 +213,3 @@
     Memcheck:Addr2
     fun:_ZN22GrAAConvexPathRenderer10onDrawPathERK6SkPathRK11SkStrokeRecP12GrDrawTargetb
 }
-
-{
-    sk_task_group_thread_pool_intentionally_leaks_in_Release_mode
-    Memcheck:Leak
-    ...
-    fun:_ZN8SkThreadC1EPFvPvES0_
-    ...
-    fun:_ZN11SkTaskGroup3addEP10SkRunnable
-}