applypatch: Consolidate CacheSizeCheck() and MakeFreeSpaceOnCache().

They are doing exactly the same thing, except for the slightly different
error return value (1 vs -1).

int CacheSizeCheck(size_t bytes);
int MakeFreeSpaceOnCache(size_t bytes_needed);

This CL consolidates the two functions and uses bool as its return type.

// Checks whether /cache partition has at least 'bytes'-byte free space. Returns true immediately
// if so. Otherwise, it will try to free some space by removing older logs, checks again and
// returns the checking result.
bool CheckAndFreeSpaceOnCache(size_t bytes);

Test: Run recovery_unit_test and recovery_component_test on marlin.
Change-Id: I94a96934d2b18713f8f39ad5aa96a02c98d87963
diff --git a/applypatch/applypatch.cpp b/applypatch/applypatch.cpp
index 13e4b1a..12e1399 100644
--- a/applypatch/applypatch.cpp
+++ b/applypatch/applypatch.cpp
@@ -420,14 +420,6 @@
   return done;
 }
 
-int CacheSizeCheck(size_t bytes) {
-  if (MakeFreeSpaceOnCache(bytes) < 0) {
-    LOG(ERROR) << "Failed to make " << bytes << " bytes available on /cache";
-    return 1;
-  }
-  return 0;
-}
-
 int applypatch(const char* source_filename, const char* target_filename,
                const char* target_sha1_str, size_t /* target_size */,
                const std::vector<std::string>& patch_sha1s,
@@ -562,8 +554,8 @@
 
   CHECK(android::base::StartsWith(target_filename, "EMMC:"));
 
-  // We still write the original source to cache, in case the partition write is interrupted.
-  if (MakeFreeSpaceOnCache(source_file.data.size()) < 0) {
+  // We write the original source to cache, in case the partition write is interrupted.
+  if (!CheckAndFreeSpaceOnCache(source_file.data.size())) {
     LOG(ERROR) << "Not enough free space on /cache";
     return 1;
   }