Revert of Collect information about failing histogram factory calls. (patchset #8 id:240001 of https://codereview.chromium.org/1719363002/ )

Reason for revert:
Confirmed in 51.0.2674.  Reverting while crashes are analyzed.

Original issue's description:
> Collect information about failing histogram factory calls.
>
> Some tests need to be disabled because they create the same histogram with different parameters, a condition which does not always crash in the calling code but does with this CL.
>
> This CL will be reverted once the necessary information has been collected, including re-enabling of any tests.
>
> SHERIFFS: If a test breaks in the waterfall, you can either revert this CL or disable the test.  I'll re-enable it when reverting this after the necessary data has been collected.
>
> BUG=588946
>
> Committed: https://crrev.com/ce1315b94863f40d6323fa488490ed866aae4ed4
> Cr-Commit-Position: refs/heads/master@{#378957}
>
> Committed: https://crrev.com/63f1c5d846f6dac2cf148b81961c38b88ff1bd86
> Cr-Commit-Position: refs/heads/master@{#379323}
>
> Committed: https://crrev.com/89dca78efa00acb8fc8749adcc1a08a24eb105d5
> Cr-Commit-Position: refs/heads/master@{#379489}
>
> Committed: https://crrev.com/1375777f66fcf8edd3f393dadd9d9de6a7409030
> Cr-Commit-Position: refs/heads/master@{#379690}
>
> Committed: https://crrev.com/0abc5c2d2cb7ac70e26eab73d7e3f61f0472461e
> Cr-Commit-Position: refs/heads/master@{#380070}
>
> Committed: https://crrev.com/1d50ab3eec1dab7d3a6c70ec85b8937d5073b66d
> Cr-Commit-Position: refs/heads/master@{#380474}

TBR=asvitkine@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=588946

Review URL: https://codereview.chromium.org/1777223004

Cr-Commit-Position: refs/heads/master@{#380612}

6 files changed, 14 insertions, 125 deletions

diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index 7feacdb..ea4f816 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -154,22 +154,10 @@ HistogramBase* Histogram::Factory::Build() {
   ImportPersistentHistograms();
 
   HistogramBase* histogram = StatisticsRecorder::FindHistogram(name_);
-
-  // crbug.com/588946 debugging. See comment at end of function.
-  const BucketRanges* created_ranges =
-      reinterpret_cast<const BucketRanges*>(0xDEADBEEF);
-  const BucketRanges* registered_ranges =
-      reinterpret_cast<const BucketRanges*>(0xDEADBEEF);
-  HistogramBase* tentative_histogram =
-      reinterpret_cast<HistogramBase*>(0xDEADBEEF);
-  PersistentMemoryAllocator* allocator =
-      reinterpret_cast<PersistentMemoryAllocator*>(0xDEADBEEF);
-  PersistentMemoryAllocator::Reference histogram_ref = 0xDEADBEEF;
-
   if (!histogram) {
     // To avoid racy destruction at shutdown, the following will be leaked.
-    created_ranges = CreateRanges();
-    registered_ranges =
+    const BucketRanges* created_ranges = CreateRanges();
+    const BucketRanges* registered_ranges =
         StatisticsRecorder::RegisterOrDeleteDuplicateRanges(created_ranges);
 
     // In most cases, the bucket-count, minimum, and maximum values are known
@@ -182,17 +170,15 @@ HistogramBase* Histogram::Factory::Build() {
       minimum_ = registered_ranges->range(1);
       maximum_ = registered_ranges->range(bucket_count_ - 1);
     }
-    CHECK_LT(0, minimum_);
-    CHECK_LT(0, maximum_);
 
     // Try to create the histogram using a "persistent" allocator. As of
     // 2015-01-14, the availability of such is controlled by a base::Feature
     // that is off by default. If the allocator doesn't exist or if
     // allocating from it fails, code below will allocate the histogram from
     // the process heap.
-    histogram_ref = 0;
-    tentative_histogram = nullptr;
-    allocator =
+    PersistentMemoryAllocator::Reference histogram_ref = 0;
+    HistogramBase* tentative_histogram = nullptr;
+    PersistentMemoryAllocator* allocator =
         GetPersistentHistogramMemoryAllocator();
     if (allocator) {
       flags_ |= HistogramBase::kIsPersistent;
@@ -205,12 +191,6 @@ HistogramBase* Histogram::Factory::Build() {
           registered_ranges,
           flags_,
           &histogram_ref);
-      CHECK_LT(0, minimum_);
-      CHECK_LT(0, maximum_);
-      CHECK_EQ(minimum_,
-               static_cast<Histogram*>(tentative_histogram)->declared_min_);
-      CHECK_EQ(maximum_,
-               static_cast<Histogram*>(tentative_histogram)->declared_max_);
     }
 
     // Handle the case where no persistent allocator is present or the
@@ -220,12 +200,6 @@ HistogramBase* Histogram::Factory::Build() {
       DCHECK(!allocator);  // Shouldn't have failed.
       flags_ &= ~HistogramBase::kIsPersistent;
       tentative_histogram = HeapAlloc(registered_ranges);
-      CHECK_LT(0, minimum_);
-      CHECK_LT(0, maximum_);
-      CHECK_EQ(minimum_,
-               static_cast<Histogram*>(tentative_histogram)->declared_min_);
-      CHECK_EQ(maximum_,
-               static_cast<Histogram*>(tentative_histogram)->declared_max_);
     }
 
     FillHistogram(tentative_histogram);
@@ -240,15 +214,6 @@ HistogramBase* Histogram::Factory::Build() {
   }
 
   DCHECK_EQ(histogram_type_, histogram->GetHistogramType());
-  bool bad_args = false;
-  HistogramBase* existing_histogram = histogram;
-  HistogramType existing_type = histogram->GetHistogramType();
-  const char* existing_name = histogram->histogram_name().c_str();
-  Sample existing_minimum = static_cast<Histogram*>(histogram)->declared_min_;
-  Sample existing_maximum = static_cast<Histogram*>(histogram)->declared_max_;
-  uint32_t existing_bucket_count =
-    static_cast<Histogram*>(histogram)->bucket_count();
-
   if (bucket_count_ != 0 &&
       !histogram->HasConstructionArguments(minimum_, maximum_, bucket_count_)) {
     // The construction arguments do not match the existing histogram.  This can
@@ -258,45 +223,8 @@ HistogramBase* Histogram::Factory::Build() {
     // on dereference, but extension/Pepper APIs will guard against NULL and not
     // crash.
     DLOG(ERROR) << "Histogram " << name_ << " has bad construction arguments";
-    bad_args = true;
-    histogram = nullptr;
-  }
-
-#if !DCHECK_IS_ON()  // Don't affect tests, only release builds.
-  // For the moment, crash here so that collected crash reports have access
-  // to the construction values in order to figure out why this is failing.
-  // TODO(bcwhite): Remove this once crbug.com/588946 is resolved. Also remove
-  // from beta-branch because we don't want crashes due to misbehaving
-  // extensions (see comment above).
-  if (!histogram) {
-    HistogramType histogram_type = histogram_type_;
-    HistogramBase::Sample minimum = minimum_;
-    HistogramBase::Sample maximum = maximum_;
-    uint32_t bucket_count = bucket_count_;
-    int32_t flags = flags_;
-    CHECK(histogram) << name_ << ": bad-args=" << bad_args;
-    base::debug::Alias(&histogram_type);
-    base::debug::Alias(&minimum);
-    base::debug::Alias(&maximum);
-    base::debug::Alias(&bucket_count);
-    base::debug::Alias(&flags);
-    base::debug::Alias(&created_ranges);
-    base::debug::Alias(&registered_ranges);
-    base::debug::Alias(&histogram_ref);
-    base::debug::Alias(&tentative_histogram);
-    base::debug::Alias(&allocator);
-    base::debug::Alias(&tentative_histogram);
+    return nullptr;
   }
-#endif
-
-  // Down here so vars are always "used".
-  base::debug::Alias(&bad_args);
-  base::debug::Alias(&existing_histogram);
-  base::debug::Alias(&existing_type);
-  base::debug::Alias(&existing_name);
-  base::debug::Alias(&existing_minimum);
-  base::debug::Alias(&existing_maximum);
-  base::debug::Alias(&existing_bucket_count);
   return histogram;
 }
 
@@ -558,12 +486,8 @@ Histogram::Histogram(const std::string& name,
     bucket_ranges_(ranges),
     declared_min_(minimum),
     declared_max_(maximum) {
-  CHECK_LT(0, minimum);
-  CHECK_LT(0, maximum);
   if (ranges)
     samples_.reset(new SampleVector(HashMetricName(name), ranges));
-  CHECK_EQ(minimum, declared_min_);
-  CHECK_EQ(maximum, declared_max_);
 }
 
 Histogram::Histogram(const std::string& name,
@@ -579,16 +503,12 @@ Histogram::Histogram(const std::string& name,
     bucket_ranges_(ranges),
     declared_min_(minimum),
     declared_max_(maximum) {
-  CHECK_LT(0, minimum);
-  CHECK_LT(0, maximum);
   if (ranges) {
     samples_.reset(new SampleVector(HashMetricName(name),
                                     counts, counts_size, meta, ranges));
     logged_samples_.reset(new SampleVector(samples_->id(), logged_counts,
                                            counts_size, logged_meta, ranges));
   }
-  CHECK_EQ(minimum, declared_min_);
-  CHECK_EQ(maximum, declared_max_);
 }
 
 Histogram::~Histogram() {
diff --git a/base/metrics/histogram_persistence.cc b/base/metrics/histogram_persistence.cc
index 34b3100..f18d175 100644
--- a/base/metrics/histogram_persistence.cc
+++ b/base/metrics/histogram_persistence.cc
@@ -244,12 +244,6 @@ HistogramBase* CreatePersistentHistogram(
   // validated below; the local copy is to ensure that the contents cannot
   // be externally changed between validation and use.
   PersistentHistogramData histogram_data = *histogram_data_ptr;
-  CHECK_EQ(histogram_data.histogram_type, histogram_data_ptr->histogram_type);
-  CHECK_EQ(histogram_data.flags, histogram_data_ptr->flags);
-  CHECK_EQ(histogram_data.minimum, histogram_data_ptr->minimum);
-  CHECK_EQ(histogram_data.maximum, histogram_data_ptr->maximum);
-  CHECK_EQ(histogram_data.bucket_count, histogram_data_ptr->bucket_count);
-  CHECK_EQ(histogram_data.ranges_checksum, histogram_data_ptr->ranges_checksum);
 
   HistogramBase::Sample* ranges_data =
       allocator->GetAsObject<HistogramBase::Sample>(histogram_data.ranges_ref,
@@ -294,8 +288,6 @@ HistogramBase* CreatePersistentHistogram(
   HistogramBase::AtomicCount* logged_data =
       counts_data + histogram_data.bucket_count;
 
-  CHECK_LT(0, histogram_data.minimum);
-  CHECK_LT(0, histogram_data.maximum);
   std::string name(histogram_data_ptr->name);
   HistogramBase* histogram = nullptr;
   switch (histogram_data.histogram_type) {
diff --git a/base/metrics/histogram_unittest.cc b/base/metrics/histogram_unittest.cc
index e6aefd3..beb6a71 100644
--- a/base/metrics/histogram_unittest.cc
+++ b/base/metrics/histogram_unittest.cc
@@ -668,7 +668,7 @@ TEST_P(HistogramTest, CustomHistogramSerializeInfo) {
   EXPECT_FALSE(iter.SkipBytes(1));
 }
 
-TEST_P(HistogramTest, DISABLED_BadConstruction) {
+TEST_P(HistogramTest, BadConstruction) {
   HistogramBase* histogram = Histogram::FactoryGet(
       "BadConstruction", 0, 100, 8, HistogramBase::kNoFlags);
   EXPECT_TRUE(histogram->HasConstructionArguments(1, 100, 8));
diff --git a/base/metrics/metrics_hashes.cc b/base/metrics/metrics_hashes.cc
index 54c117b..5672b06 100644
--- a/base/metrics/metrics_hashes.cc
+++ b/base/metrics/metrics_hashes.cc
@@ -4,7 +4,6 @@
 
 #include "base/metrics/metrics_hashes.h"
 
-#include "base/debug/alias.h"
 #include "base/logging.h"
 #include "base/md5.h"
 #include "base/sys_byteorder.h"
@@ -16,14 +15,9 @@ namespace {
 // Converts the 8-byte prefix of an MD5 hash into a uint64_t value.
 inline uint64_t DigestToUInt64(const base::MD5Digest& digest) {
   uint64_t value;
-  CHECK_GE(sizeof(digest.a), sizeof(value));
+  DCHECK_GE(sizeof(digest.a), sizeof(value));
   memcpy(&value, digest.a, sizeof(value));
-  uint64_t hash = base::NetToHost64(value);
-  CHECK_NE(0U, hash);
-  base::debug::Alias(&hash);
-  base::debug::Alias(&value);
-  base::debug::Alias(&digest);
-  return hash;
+  return base::NetToHost64(value);
 }
 
 }  // namespace
diff --git a/base/metrics/statistics_recorder.cc b/base/metrics/statistics_recorder.cc
index 90d64bb..d0fa2ad 100644
--- a/base/metrics/statistics_recorder.cc
+++ b/base/metrics/statistics_recorder.cc
@@ -5,7 +5,6 @@
 #include "base/metrics/statistics_recorder.h"
 
 #include "base/at_exit.h"
-#include "base/debug/alias.h"
 #include "base/debug/leak_annotations.h"
 #include "base/json/string_escape.h"
 #include "base/logging.h"
@@ -124,17 +123,13 @@ HistogramBase* StatisticsRecorder::RegisterOrDeleteDuplicate(
         histogram_to_return = histogram;
       } else {
         // We already have one histogram with this name.
-        CHECK_EQ(histogram->histogram_name(),
-                 it->second->histogram_name()) << "hash collision";
+        DCHECK_EQ(histogram->histogram_name(),
+                  it->second->histogram_name()) << "hash collision";
         histogram_to_return = it->second;
         histogram_to_delete = histogram;
       }
-      base::debug::Alias(&it);
-      base::debug::Alias(&name);
-      base::debug::Alias(&name_hash);
     }
   }
-  base::debug::Alias(&histogram);
   delete histogram_to_delete;
   return histogram_to_return;
 }
@@ -284,22 +279,10 @@ HistogramBase* StatisticsRecorder::FindHistogram(base::StringPiece name) {
   if (histograms_ == NULL)
     return NULL;
 
-  const uint64_t lookup_hash = HashMetricName(name);
-  HistogramMap::iterator it = histograms_->find(lookup_hash);
+  HistogramMap::iterator it = histograms_->find(HashMetricName(name));
   if (histograms_->end() == it)
     return NULL;
-
-  const uint64_t existing_hash = it->first;
-  const char* existing_name = it->second->histogram_name().c_str();
-  HistogramMap* histograms = histograms_;
-  CHECK_EQ(name, it->second->histogram_name()) << "hash collision";
-  base::debug::Alias(&lookup_hash);
-  base::debug::Alias(&existing_hash);
-  base::debug::Alias(&name);
-  base::debug::Alias(&existing_name);
-  base::debug::Alias(&it);
-  base::debug::Alias(&histograms);
-
+  DCHECK_EQ(name, it->second->histogram_name()) << "hash collision";
   return it->second;
 }
 
diff --git a/chrome/browser/extensions/api/metrics_private/metrics_apitest.cc b/chrome/browser/extensions/api/metrics_private/metrics_apitest.cc
index d4c5e3c..3160400 100644
--- a/chrome/browser/extensions/api/metrics_private/metrics_apitest.cc
+++ b/chrome/browser/extensions/api/metrics_private/metrics_apitest.cc
@@ -128,7 +128,7 @@ void ValidateHistograms(const RecordedHistogram* recorded,
 
 }  // anonymous namespace
 
-IN_PROC_BROWSER_TEST_F(ExtensionApiTest, DISABLED_Metrics) {
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, Metrics) {
   base::UserActionTester user_action_tester;
 
   base::FieldTrialList::CreateFieldTrial("apitestfieldtrial2", "group1");