wtf: Add erase(iterator, iterator) overload to support erase-remove idiom

Bug: 1029379
Change-Id: I4642e31fd3f39469ee1f94045228027da736a61a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2066921Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743503}

third_party/blink/renderer/platform/wtf/vector.h

@@ -1237,6 +1237,9 @@ class Vector
   void EraseAt(wtf_size_t position);
   void EraseAt(wtf_size_t position, wtf_size_t length);
   iterator erase(iterator position);
+  iterator erase(iterator first, iterator last);
+  // This is to prevent compilation of deprecated calls like 'vector.erase(0)'.
+  void erase(std::nullptr_t) = delete;
 
   // Remove the last element. Unlike remove(), (1) this function is fast, and
   // (2) only iterators pointing to the last element will be invalidated. Other
@@ -1326,9 +1329,6 @@ class Vector
 
   void ReallocateBuffer(wtf_size_t);
 
-  // This is to prevent compilation of deprecated calls like 'vector.erase(0)'.
-  void erase(std::nullptr_t) = delete;
-
   using Base::size_;
   using Base::Buffer;
   using Base::SwapVectorBuffer;
@@ -1921,6 +1921,17 @@ inline auto Vector<T, inlineCapacity, Allocator>::erase(iterator position)
   return begin() + index;
 }
 
+template <typename T, wtf_size_t inlineCapacity, typename Allocator>
+inline auto Vector<T, inlineCapacity, Allocator>::erase(iterator first,
+                                                        iterator last)
+    -> iterator {
+  DCHECK_LE(first, last);
+  const wtf_size_t index = static_cast<wtf_size_t>(first - begin());
+  const wtf_size_t diff = std::distance(first, last);
+  EraseAt(index, diff);
+  return begin() + index;
+}
+
 template <typename T, wtf_size_t inlineCapacity, typename Allocator>
 inline void Vector<T, inlineCapacity, Allocator>::EraseAt(wtf_size_t position,
                                                           wtf_size_t length) {

third_party/blink/renderer/platform/wtf/vector_test.cc

@@ -101,22 +101,34 @@ TEST(VectorTest, EraseAtIndex) {
 }
 
 TEST(VectorTest, Erase) {
-  Vector<int> int_vector({0, 1, 2, 3});
+  Vector<int> int_vector({0, 1, 2, 3, 4, 5});
 
-  EXPECT_EQ(4u, int_vector.size());
+  EXPECT_EQ(6u, int_vector.size());
   EXPECT_EQ(0, int_vector[0]);
   EXPECT_EQ(1, int_vector[1]);
   EXPECT_EQ(2, int_vector[2]);
   EXPECT_EQ(3, int_vector[3]);
+  EXPECT_EQ(4, int_vector[4]);
+  EXPECT_EQ(5, int_vector[5]);
 
   auto* first = int_vector.erase(int_vector.begin());
-  EXPECT_EQ(3u, int_vector.size());
+  EXPECT_EQ(5u, int_vector.size());
   EXPECT_EQ(1, *first);
   EXPECT_EQ(int_vector.begin(), first);
 
-  auto* last = std::lower_bound(int_vector.begin(), int_vector.end(), 3);
+  auto* last = std::lower_bound(int_vector.begin(), int_vector.end(), 5);
   auto* end = int_vector.erase(last);
+  EXPECT_EQ(4u, int_vector.size());
+  EXPECT_EQ(int_vector.end(), end);
+
+  auto* item2 = std::lower_bound(int_vector.begin(), int_vector.end(), 2);
+  auto* item4 = int_vector.erase(item2, item2 + 2);
   EXPECT_EQ(2u, int_vector.size());
+  EXPECT_EQ(4, *item4);
+
+  last = std::lower_bound(int_vector.begin(), int_vector.end(), 4);
+  end = int_vector.erase(last, int_vector.end());
+  EXPECT_EQ(1u, int_vector.size());
   EXPECT_EQ(int_vector.end(), end);
 }