FBTF: Fix more ctor/dtors found by clang plugin.

gpu/command_buffer/client/fenced_allocator.cc

Index: gpu/command_buffer/client/fenced_allocator.cc
diff --git a/gpu/command_buffer/client/fenced_allocator.cc b/gpu/command_buffer/client/fenced_allocator.cc
index 3fc625d5b8fd8c6de9a18841e1bf617f5976489a..f105f3a50ea3e23b6045f798831af085aebd3e2b 100644
--- a/gpu/command_buffer/client/fenced_allocator.cc
+++ b/gpu/command_buffer/client/fenced_allocator.cc
@@ -14,6 +14,13 @@ namespace gpu {
 const FencedAllocator::Offset FencedAllocator::kInvalidOffset;
 #endif
 
+FencedAllocator::FencedAllocator(unsigned int size,
+                                 CommandBufferHelper *helper)
+    : helper_(helper) {
+  Block block = { FREE, 0, size, kUnusedToken };
+  blocks_.push_back(block);
+}
+
 FencedAllocator::~FencedAllocator() {
   // Free blocks pending tokens.
   for (unsigned int i = 0; i < blocks_.size(); ++i) {