Revert of Combine 'pssh' parsing routines. (patchset #8 id:140001 of https://codereview.chromium.org/1149023002/)

Reason for revert:
Breaks compile on 'Google Chrome Win' bot:
https://build.chromium.org/p/chromium.chrome/builders/Google%20Chrome%20Win/builds/1066

Original issue's description:
> Combine CENC 'pssh' box parsing routines.
>
> Also update the routines to ignore 'pssh' boxes with version 2 or
> later.
>
> BUG=460359, 460360
> TEST=new unittests pass
>
> Committed: https://crrev.com/b666d7874efac44b359a95329f0cb890e97671df
> Cr-Commit-Position: refs/heads/master@{#333556}
>
> Committed: https://crrev.com/7a84443597e92a03f90806712f8629df40bf408e
> Cr-Commit-Position: refs/heads/master@{#333611}

TBR=sandersd@chromium.org,ddorwin@chromium.org,xhwang@chromium.org,jrummell@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=460359, 460360

Review URL: https://codereview.chromium.org/1165313003

Cr-Commit-Position: refs/heads/master@{#333694}

7 files changed, 195 insertions, 390 deletions

diff --git a/media/cdm/cenc_utils.cc b/media/cdm/cenc_utils.cc
index 495a6f2..86779b2 100644
--- a/media/cdm/cenc_utils.cc
+++ b/media/cdm/cenc_utils.cc
@@ -4,9 +4,7 @@
 
 #include "media/cdm/cenc_utils.h"
 
-#include "base/stl_util.h"
-#include "media/formats/mp4/box_definitions.h"
-#include "media/formats/mp4/box_reader.h"
+#include "media/base/bit_reader.h"
 
 namespace media {
 
@@ -14,6 +12,31 @@ namespace media {
 // Encryption ('cenc') protection scheme may contain one or more protection
 // system specific header ('pssh') boxes.
 // ref: https://w3c.github.io/encrypted-media/cenc-format.html
+//
+// The format of a 'pssh' box is as follows:
+//   unsigned int(32) size;
+//   unsigned int(32) type = "pssh";
+//   if (size==1) {
+//     unsigned int(64) largesize;
+//   } else if (size==0) {
+//     -- box extends to end of file
+//   }
+//   unsigned int(8) version;
+//   bit(24) flags;
+//   unsigned int(8)[16] SystemID;
+//   if (version > 0)
+//   {
+//     unsigned int(32) KID_count;
+//     {
+//       unsigned int(8)[16] KID;
+//     } [KID_count]
+//   }
+//   unsigned int(32) DataSize;
+//   unsigned int(8)[DataSize] Data;
+
+// Minimum size of a 'pssh' box includes  all the required fields (size, type,
+// version, flags, SystemID, DataSize).
+const int kMinimumBoxSizeInBytes = 32;
 
 // SystemID for the Common System.
 // https://w3c.github.io/encrypted-media/cenc-format.html#common-system
@@ -22,102 +45,136 @@ const uint8_t kCommonSystemId[] = { 0x10, 0x77, 0xef, 0xec,
                                     0xac, 0xe3, 0x3c, 0x1e,
                                     0x52, 0xe2, 0xfb, 0x4b };
 
-static bool ReadAllPsshBoxes(
-    const std::vector<uint8_t>& input,
-    std::vector<mp4::FullProtectionSystemSpecificHeader>* pssh_boxes) {
-  DCHECK(!input.empty());
-
-  // Verify that |input| contains only 'pssh' boxes. ReadAllChildren() is
-  // templated, so it checks that each box in |input| matches the box type of
-  // the parameter (in this case mp4::ProtectionSystemSpecificHeader is a
-  // 'pssh' box). mp4::ProtectionSystemSpecificHeader doesn't validate the
-  // 'pssh' contents, so this simply verifies that |input| only contains
-  // 'pssh' boxes and nothing else.
-  scoped_ptr<mp4::BoxReader> input_reader(
-      mp4::BoxReader::ReadConcatentatedBoxes(
-          vector_as_array(&input), input.size()));
-  std::vector<mp4::ProtectionSystemSpecificHeader> raw_pssh_boxes;
-  if (!input_reader->ReadAllChildren(&raw_pssh_boxes))
-    return false;
-
-  // Now that we have |input| parsed into |raw_pssh_boxes|, reparse each one
-  // into a mp4::FullProtectionSystemSpecificHeader, which extracts all the
-  // relevant fields from the box. Since there may be unparseable 'pssh' boxes
-  // (due to unsupported version, for example), this is done one by one,
-  // ignoring any boxes that can't be parsed.
-  for (const auto& raw_pssh_box : raw_pssh_boxes) {
-    scoped_ptr<mp4::BoxReader> raw_pssh_reader(
-        mp4::BoxReader::ReadConcatentatedBoxes(
-            vector_as_array(&raw_pssh_box.raw_box),
-            raw_pssh_box.raw_box.size()));
-    // ReadAllChildren() appends any successfully parsed box onto it's
-    // parameter, so |pssh_boxes| will contain the collection of successfully
-    // parsed 'pssh' boxes. If an error occurs, try the next box.
-    if (!raw_pssh_reader->ReadAllChildren(pssh_boxes))
-      continue;
+#define RCHECK(x)   \
+  do {              \
+    if (!(x))       \
+      return false; \
+  } while (0)
+
+// Helper function to read up to 32 bits from a bit stream.
+static uint32_t ReadBits(BitReader* reader, int num_bits) {
+  DCHECK_GE(reader->bits_available(), num_bits);
+  DCHECK((num_bits > 0) && (num_bits <= 32));
+  uint32_t value;
+  reader->ReadBits(num_bits, &value);
+  return value;
+}
+
+// Checks whether the next 16 bytes matches the Common SystemID.
+// Assumes |reader| has enough data.
+static bool IsCommonSystemID(BitReader* reader) {
+  for (uint32_t i = 0; i < arraysize(kCommonSystemId); ++i) {
+    if (ReadBits(reader, 8) != kCommonSystemId[i])
+      return false;
+  }
+  return true;
+}
+
+// Checks that |reader| contains a valid 'ppsh' box header. |reader| is updated
+// to point to the content immediately following the box header. Returns true
+// if the header looks valid and |reader| contains enough data for the size of
+// header. |size| is updated as the computed size of the box header. Otherwise
+// false is returned.
+static bool ValidBoxHeader(BitReader* reader, uint32* size) {
+  // Enough data for a miniumum size 'pssh' box?
+  uint32 available_bytes = reader->bits_available() / 8;
+  RCHECK(available_bytes >= kMinimumBoxSizeInBytes);
+
+  *size = ReadBits(reader, 32);
+
+  // Must be a 'pssh' box or else fail.
+  RCHECK(ReadBits(reader, 8) == 'p');
+  RCHECK(ReadBits(reader, 8) == 's');
+  RCHECK(ReadBits(reader, 8) == 's');
+  RCHECK(ReadBits(reader, 8) == 'h');
+
+  if (*size == 1) {
+    // If largesize > 2**32 it is too big.
+    RCHECK(ReadBits(reader, 32) == 0);
+    *size = ReadBits(reader, 32);
+  } else if (*size == 0) {
+    *size = available_bytes;
   }
 
-  // Must have successfully parsed at least one 'pssh' box.
-  return pssh_boxes->size() > 0;
+  // Check that the buffer contains at least size bytes.
+  return available_bytes >= *size;
 }
 
 bool ValidatePsshInput(const std::vector<uint8_t>& input) {
-  // No 'pssh' boxes is considered valid.
-  if (input.empty())
-    return true;
+  size_t offset = 0;
+  while (offset < input.size()) {
+    // Create a BitReader over the remaining part of the buffer.
+    BitReader reader(&input[offset], input.size() - offset);
+    uint32 size;
+    RCHECK(ValidBoxHeader(&reader, &size));
+
+    // Update offset to point at the next 'pssh' box (may not be one).
+    offset += size;
+  }
 
-  std::vector<mp4::FullProtectionSystemSpecificHeader> children;
-  return ReadAllPsshBoxes(input, &children);
+  // Only valid if this contains 0 or more 'pssh' boxes.
+  return offset == input.size();
 }
 
 bool GetKeyIdsForCommonSystemId(const std::vector<uint8_t>& input,
                                 KeyIdList* key_ids) {
+  size_t offset = 0;
   KeyIdList result;
-  std::vector<uint8_t> common_system_id(
-      kCommonSystemId, kCommonSystemId + arraysize(kCommonSystemId));
 
-  if (!input.empty()) {
-    std::vector<mp4::FullProtectionSystemSpecificHeader> children;
-    if (!ReadAllPsshBoxes(input, &children))
-      return false;
+  while (offset < input.size()) {
+    BitReader reader(&input[offset], input.size() - offset);
+    uint32 size;
+    RCHECK(ValidBoxHeader(&reader, &size));
+
+    // Update offset to point at the next 'pssh' box (may not be one).
+    offset += size;
+
+    // Check the version, as KIDs only available if version > 0.
+    uint8_t version = ReadBits(&reader, 8);
+    if (version == 0)
+      continue;
+
+    // flags must be 0. If not, assume incorrect 'pssh' box and move to the
+    // next one.
+    if (ReadBits(&reader, 24) != 0)
+      continue;
+
+    // Validate SystemID
+    RCHECK(static_cast<uint32_t>(reader.bits_available()) >=
+           arraysize(kCommonSystemId) * 8);
+    if (!IsCommonSystemID(&reader))
+      continue;  // Not Common System, so try the next pssh box.
 
-    // Check all children for an appropriate 'pssh' box, concatenating any
-    // key IDs found.
-    for (const auto& child : children) {
-      if (child.system_id == common_system_id && child.key_ids.size() > 0)
-        result.insert(result.end(), child.key_ids.begin(), child.key_ids.end());
+    // Since version > 0, next field is the KID_count.
+    RCHECK(static_cast<uint32_t>(reader.bits_available()) >=
+           sizeof(uint32_t) * 8);
+    uint32_t count = ReadBits(&reader, 32);
+
+    if (count == 0)
+      continue;
+
+    // Make sure there is enough data for all the KIDs specified, and then
+    // extract them.
+    RCHECK(static_cast<uint32_t>(reader.bits_available()) > count * 16 * 8);
+    while (count > 0) {
+      std::vector<uint8_t> key;
+      key.reserve(16);
+      for (int i = 0; i < 16; ++i) {
+        key.push_back(ReadBits(&reader, 8));
+      }
+      result.push_back(key);
+      --count;
     }
+
+    // Don't bother checking DataSize and Data.
   }
 
-  // No matching 'pssh' box found.
+  key_ids->swap(result);
+
   // TODO(jrummell): This should return true only if there was at least one
   // key ID present. However, numerous test files don't contain the 'pssh' box
   // for Common Format, so no keys are found. http://crbug.com/460308
-  key_ids->swap(result);
   return true;
 }
 
-bool GetPsshData(const std::vector<uint8_t>& input,
-                 const std::vector<uint8_t>& system_id,
-                 std::vector<uint8_t>* pssh_data) {
-  if (input.empty())
-    return false;
-
-  std::vector<mp4::FullProtectionSystemSpecificHeader> children;
-  if (!ReadAllPsshBoxes(input, &children))
-    return false;
-
-  // Check all children for an appropriate 'pssh' box, returning |data| from
-  // the first one found.
-  for (const auto& child : children) {
-    if (child.system_id == system_id) {
-      pssh_data->assign(child.data.begin(), child.data.end());
-      return true;
-    }
-  }
-
-  // No matching 'pssh' box found.
-  return false;
-}
-
 }  // namespace media
diff --git a/media/cdm/cenc_utils.h b/media/cdm/cenc_utils.h
index 7dd82a1..ec85fb3 100644
--- a/media/cdm/cenc_utils.h
+++ b/media/cdm/cenc_utils.h
@@ -28,17 +28,6 @@ MEDIA_EXPORT bool ValidatePsshInput(const std::vector<uint8_t>& input);
 MEDIA_EXPORT bool GetKeyIdsForCommonSystemId(const std::vector<uint8_t>& input,
                                              KeyIdList* key_ids);
 
-// Gets the data field from the first 'pssh' box containing |system_id| UUID.
-// Returns true if such a box is found and successfully parsed. Returns false
-// otherwise.
-// Notes:
-// 1. If multiple PSSH boxes are found, the "Data" of the first matching 'pssh'
-//    box will be set in |pssh_data|.
-// 2. Only PSSH boxes are allowed in |input|.
-MEDIA_EXPORT bool GetPsshData(const std::vector<uint8_t>& input,
-                              const std::vector<uint8_t>& system_id,
-                              std::vector<uint8_t>* pssh_data);
-
 }  // namespace media
 
 #endif  // MEDIA_CDM_CENC_UTILS_H_
diff --git a/media/cdm/cenc_utils_unittest.cc b/media/cdm/cenc_utils_unittest.cc
index 2e7ead2..9923619 100644
--- a/media/cdm/cenc_utils_unittest.cc
+++ b/media/cdm/cenc_utils_unittest.cc
@@ -25,10 +25,6 @@ const uint8_t kKey4Data[] = {
     0x7E, 0x57, 0x1D, 0x04, 0x7E, 0x57, 0x1D, 0x06,
     0x7E, 0x57, 0x1D, 0x04, 0x7E, 0x57, 0x1D, 0x06,
 };
-const uint8_t kCommonSystemSystemId[] = {
-    0x10, 0x77, 0xEF, 0xEC, 0xC0, 0xB2, 0x4D, 0x02,
-    0xAC, 0xE3, 0x3C, 0x1E, 0x52, 0xE2, 0xFB, 0x4B
-};
 
 class CencUtilsTest : public testing::Test {
  public:
@@ -36,10 +32,7 @@ class CencUtilsTest : public testing::Test {
       : key1_(kKey1Data, kKey1Data + arraysize(kKey1Data)),
         key2_(kKey2Data, kKey2Data + arraysize(kKey2Data)),
         key3_(kKey3Data, kKey3Data + arraysize(kKey3Data)),
-        key4_(kKey4Data, kKey4Data + arraysize(kKey4Data)),
-        common_system_system_id_(
-            kCommonSystemSystemId,
-            kCommonSystemSystemId + arraysize(kCommonSystemSystemId)) {}
+        key4_(kKey4Data, kKey4Data + arraysize(kKey4Data)) {}
 
  protected:
   // Initialize the start of the 'pssh' box (up to key_count)
@@ -65,9 +58,23 @@ class CencUtilsTest : public testing::Test {
     box->push_back(0);
     box->push_back(0);
     box->push_back(0);
-    // Add Common Encryption SystemID.
-    box->insert(box->end(), common_system_system_id_.begin(),
-                common_system_system_id_.end());
+    // Add Clear Key SystemID.
+    box->push_back(0x10);
+    box->push_back(0x77);
+    box->push_back(0xEF);
+    box->push_back(0xEC);
+    box->push_back(0xC0);
+    box->push_back(0xB2);
+    box->push_back(0x4D);
+    box->push_back(0x02);
+    box->push_back(0xAC);
+    box->push_back(0xE3);
+    box->push_back(0x3C);
+    box->push_back(0x1E);
+    box->push_back(0x52);
+    box->push_back(0xE2);
+    box->push_back(0xFB);
+    box->push_back(0x4B);
   }
 
   std::vector<uint8_t> MakePSSHBox(uint8_t version) {
@@ -105,7 +112,7 @@ class CencUtilsTest : public testing::Test {
     box.push_back(1);
 
     // Add key1.
-    for (uint i = 0; i < key1.size(); ++i)
+    for (int i = 0; i < 16; ++i)
       box.push_back(key1[i]);
 
     // Add data_size (= 0).
@@ -134,11 +141,11 @@ class CencUtilsTest : public testing::Test {
     box.push_back(2);
 
     // Add key1.
-    for (uint i = 0; i < key1.size(); ++i)
+    for (int i = 0; i < 16; ++i)
       box.push_back(key1[i]);
 
     // Add key2.
-    for (uint i = 0; i < key2.size(); ++i)
+    for (int i = 0; i < 16; ++i)
       box.push_back(key2[i]);
 
     // Add data_size (= 0).
@@ -149,32 +156,16 @@ class CencUtilsTest : public testing::Test {
     return box;
   }
 
-  void AppendData(std::vector<uint8_t>& pssh_box,
-                  const std::vector<uint8_t>& data) {
-    // This assumes that |pssh_box| has been created using the routines above,
-    // and simply appends the data to the end of it. It updates the box size
-    // and sets the data size.
-    DCHECK(data.size() < 100);
-    pssh_box[3] += data.size();
-    pssh_box.pop_back();
-    pssh_box.push_back(data.size());
-    pssh_box.insert(pssh_box.end(), data.begin(), data.end());
-  }
-
   const std::vector<uint8_t>& Key1() { return key1_; }
   const std::vector<uint8_t>& Key2() { return key2_; }
   const std::vector<uint8_t>& Key3() { return key3_; }
   const std::vector<uint8_t>& Key4() { return key4_; }
-  const std::vector<uint8_t>& CommonSystemSystemId() {
-    return common_system_system_id_;
-  }
 
  private:
   std::vector<uint8_t> key1_;
   std::vector<uint8_t> key2_;
   std::vector<uint8_t> key3_;
   std::vector<uint8_t> key4_;
-  std::vector<uint8_t> common_system_system_id_;
 };
 
 TEST_F(CencUtilsTest, EmptyPSSH) {
@@ -223,8 +214,9 @@ TEST_F(CencUtilsTest, PSSHVersion0Plus1) {
   std::vector<uint8_t> box0 = MakePSSHBox(0);
   std::vector<uint8_t> box1 = MakePSSHBox(1, Key1());
 
-  // Concatentate box1 onto end of box0.
-  box0.insert(box0.end(), box1.begin(), box1.end());
+  // Concatentate box1 into box0.
+  for (const auto& value : box1)
+    box0.push_back(value);
 
   KeyIdList key_ids;
   EXPECT_TRUE(ValidatePsshInput(box0));
@@ -237,8 +229,9 @@ TEST_F(CencUtilsTest, PSSHVersion1Plus0) {
   std::vector<uint8_t> box0 = MakePSSHBox(0);
   std::vector<uint8_t> box1 = MakePSSHBox(1, Key1());
 
-  // Concatentate box0 onto end of box1.
-  box1.insert(box1.end(), box0.begin(), box0.end());
+  // Concatentate box0 into box1.
+  for (const auto& value : box0)
+    box1.push_back(value);
 
   KeyIdList key_ids;
   EXPECT_TRUE(ValidatePsshInput(box1));
@@ -252,9 +245,12 @@ TEST_F(CencUtilsTest, MultiplePSSHVersion1) {
   std::vector<uint8_t> box1 = MakePSSHBox(1, Key3());
   std::vector<uint8_t> box2 = MakePSSHBox(1, Key4());
 
-  // Concatentate box1 and box2 onto end of box.
-  box.insert(box.end(), box1.begin(), box1.end());
-  box.insert(box.end(), box2.begin(), box2.end());
+  // Concatentate box1 into box.
+  for (const auto& value : box1)
+    box.push_back(value);
+  // Concatentate box2 into box.
+  for (const auto& value : box2)
+    box.push_back(value);
 
   KeyIdList key_ids;
   EXPECT_TRUE(ValidatePsshInput(box));
@@ -272,12 +268,11 @@ TEST_F(CencUtilsTest, InvalidPSSH) {
   for (uint32 i = 1; i < box.size(); ++i) {
     // Modify size of data passed to be less than real size.
     std::vector<uint8_t> truncated(&box[0], &box[0] + i);
-    EXPECT_FALSE(ValidatePsshInput(truncated)) << "Failed for length " << i;
+    EXPECT_FALSE(ValidatePsshInput(truncated));
     EXPECT_FALSE(GetKeyIdsForCommonSystemId(truncated, &key_ids));
     // Modify starting point.
     std::vector<uint8_t> changed_offset(&box[i], &box[i] + box.size() - i);
-    EXPECT_FALSE(ValidatePsshInput(changed_offset)) << "Failed for offset "
-                                                    << i;
+    EXPECT_FALSE(ValidatePsshInput(changed_offset));
     EXPECT_FALSE(GetKeyIdsForCommonSystemId(changed_offset, &key_ids));
   }
 }
@@ -300,7 +295,9 @@ TEST_F(CencUtilsTest, InvalidFlags) {
   box[10] = 3;
 
   KeyIdList key_ids;
-  EXPECT_FALSE(GetKeyIdsForCommonSystemId(box, &key_ids));
+  // TODO(jrummell): This should fail as the 'pssh' box is skipped.
+  EXPECT_TRUE(GetKeyIdsForCommonSystemId(box, &key_ids));
+  EXPECT_EQ(0u, key_ids.size());
 }
 
 TEST_F(CencUtilsTest, LongSize) {
@@ -376,140 +373,4 @@ TEST_F(CencUtilsTest, HugeSize) {
       std::vector<uint8_t>(data, data + arraysize(data)), &key_ids));
 }
 
-TEST_F(CencUtilsTest, GetPsshData_Version0) {
-  const uint8_t data_bytes[] = {0x01, 0x02, 0x03, 0x04};
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box = MakePSSHBox(0);
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-  EXPECT_EQ(0u, pssh_data.size());
-
-  std::vector<uint8_t> data(data_bytes, data_bytes + arraysize(data_bytes));
-  AppendData(box, data);
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-  EXPECT_EQ(data, pssh_data);
-}
-
-TEST_F(CencUtilsTest, GetPsshData_Version1NoKeys) {
-  const uint8_t data_bytes[] = {0x05, 0x06, 0x07, 0x08};
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box = MakePSSHBox(1);
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-  EXPECT_EQ(0u, pssh_data.size());
-
-  std::vector<uint8_t> data(data_bytes, data_bytes + arraysize(data_bytes));
-  AppendData(box, data);
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-  EXPECT_EQ(data, pssh_data);
-}
-
-TEST_F(CencUtilsTest, GetPsshData_Version1WithKeys) {
-  const uint8_t data_bytes[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box = MakePSSHBox(1, Key1());
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-  EXPECT_EQ(0u, pssh_data.size());
-
-  std::vector<uint8_t> data(data_bytes, data_bytes + arraysize(data_bytes));
-  AppendData(box, data);
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-  EXPECT_EQ(data, pssh_data);
-}
-
-TEST_F(CencUtilsTest, GetPsshData_Version2) {
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box = MakePSSHBox(1, Key1());
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-
-  // Change the version manually, since we don't know what v2 will contain.
-  box[8] = 2;
-  EXPECT_FALSE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-}
-
-TEST_F(CencUtilsTest, GetPsshData_Version2ThenVersion1) {
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box_v1 = MakePSSHBox(1, Key1());
-  std::vector<uint8_t> box_v2 = MakePSSHBox(2, Key2(), Key3());
-
-  // Concatentate the boxes together (v2 first).
-  std::vector<uint8_t> boxes;
-  boxes.insert(boxes.end(), box_v2.begin(), box_v2.end());
-  boxes.insert(boxes.end(), box_v1.begin(), box_v1.end());
-  EXPECT_TRUE(GetPsshData(boxes, CommonSystemSystemId(), &pssh_data));
-
-  // GetKeyIdsForCommonSystemId() should return the single key from the v1
-  // 'pssh' box.
-  KeyIdList key_ids;
-  EXPECT_TRUE(GetKeyIdsForCommonSystemId(boxes, &key_ids));
-  EXPECT_EQ(1u, key_ids.size());
-  EXPECT_EQ(key_ids[0], Key1());
-}
-
-TEST_F(CencUtilsTest, GetPsshData_Version1ThenVersion2) {
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box_v1 = MakePSSHBox(1, Key3());
-  std::vector<uint8_t> box_v2 = MakePSSHBox(2, Key4());
-
-  // Concatentate the boxes together (v1 first).
-  std::vector<uint8_t> boxes;
-  boxes.insert(boxes.end(), box_v1.begin(), box_v1.end());
-  boxes.insert(boxes.end(), box_v2.begin(), box_v2.end());
-  EXPECT_TRUE(GetPsshData(boxes, CommonSystemSystemId(), &pssh_data));
-
-  // GetKeyIdsForCommonSystemId() should return the single key from the v1
-  // 'pssh' box.
-  KeyIdList key_ids;
-  EXPECT_TRUE(GetKeyIdsForCommonSystemId(boxes, &key_ids));
-  EXPECT_EQ(1u, key_ids.size());
-  EXPECT_EQ(key_ids[0], Key3());
-}
-
-TEST_F(CencUtilsTest, GetPsshData_DifferentSystemID) {
-  std::vector<uint8_t> unknown_system_id(kKey1Data,
-                                         kKey1Data + arraysize(kKey1Data));
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box = MakePSSHBox(1, Key1());
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-  EXPECT_FALSE(GetPsshData(box, unknown_system_id, &pssh_data));
-}
-
-TEST_F(CencUtilsTest, GetPsshData_MissingData) {
-  const uint8_t data_bytes[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box = MakePSSHBox(1, Key1());
-  std::vector<uint8_t> data(data_bytes, data_bytes + arraysize(data_bytes));
-  AppendData(box, data);
-  EXPECT_TRUE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-
-  // Remove some data from the end, so now the size is incorrect.
-  box.pop_back();
-  box.pop_back();
-  EXPECT_FALSE(GetPsshData(box, CommonSystemSystemId(), &pssh_data));
-}
-
-TEST_F(CencUtilsTest, GetPsshData_MultiplePssh) {
-  const uint8_t data1_bytes[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
-  const uint8_t data2_bytes[] = {0xa1, 0xa2, 0xa3, 0xa4};
-  std::vector<uint8_t> pssh_data;
-
-  std::vector<uint8_t> box1 = MakePSSHBox(1, Key1());
-  std::vector<uint8_t> data1(data1_bytes, data1_bytes + arraysize(data1_bytes));
-  AppendData(box1, data1);
-
-  std::vector<uint8_t> box2 = MakePSSHBox(0);
-  std::vector<uint8_t> data2(data2_bytes, data2_bytes + arraysize(data2_bytes));
-  AppendData(box2, data2);
-
-  box1.insert(box1.end(), box2.begin(), box2.end());
-  EXPECT_TRUE(GetPsshData(box1, CommonSystemSystemId(), &pssh_data));
-  EXPECT_EQ(data1, pssh_data);
-  EXPECT_NE(data2, pssh_data);
-}
 }  // namespace media
diff --git a/media/formats/mp4/box_definitions.cc b/media/formats/mp4/box_definitions.cc
index 72809cf..5a15240 100644
--- a/media/formats/mp4/box_definitions.cc
+++ b/media/formats/mp4/box_definitions.cc
@@ -26,65 +26,16 @@ ProtectionSystemSpecificHeader::~ProtectionSystemSpecificHeader() {}
 FourCC ProtectionSystemSpecificHeader::BoxType() const { return FOURCC_PSSH; }
 
 bool ProtectionSystemSpecificHeader::Parse(BoxReader* reader) {
-  // Don't bother validating the box's contents.
+  // Validate the box's contents and hang on to the system ID.
+  RCHECK(reader->ReadFullBoxHeader() &&
+         reader->ReadVec(&system_id, 16));
+
   // Copy the entire box, including the header, for passing to EME as initData.
   DCHECK(raw_box.empty());
   raw_box.assign(reader->data(), reader->data() + reader->size());
   return true;
 }
 
-FullProtectionSystemSpecificHeader::FullProtectionSystemSpecificHeader() {}
-FullProtectionSystemSpecificHeader::~FullProtectionSystemSpecificHeader() {}
-FourCC FullProtectionSystemSpecificHeader::BoxType() const {
-  return FOURCC_PSSH;
-}
-
-// The format of a 'pssh' box is as follows:
-//   unsigned int(32) size;
-//   unsigned int(32) type = "pssh";
-//   if (size==1) {
-//     unsigned int(64) largesize;
-//   } else if (size==0) {
-//     -- box extends to end of file
-//   }
-//   unsigned int(8) version;
-//   bit(24) flags;
-//   unsigned int(8)[16] SystemID;
-//   if (version > 0)
-//   {
-//     unsigned int(32) KID_count;
-//     {
-//       unsigned int(8)[16] KID;
-//     } [KID_count]
-//   }
-//   unsigned int(32) DataSize;
-//   unsigned int(8)[DataSize] Data;
-
-bool FullProtectionSystemSpecificHeader::Parse(mp4::BoxReader* reader) {
-  RCHECK(reader->type() == BoxType() && reader->ReadFullBoxHeader());
-
-  // Only versions 0 and 1 of the 'pssh' boxes are supported. Any other
-  // versions are ignored.
-  RCHECK(reader->version() == 0 || reader->version() == 1);
-  RCHECK(reader->flags() == 0);
-  RCHECK(reader->ReadVec(&system_id, 16));
-
-  if (reader->version() > 0) {
-    uint32_t kid_count;
-    RCHECK(reader->Read4(&kid_count));
-    for (uint32_t i = 0; i < kid_count; ++i) {
-      std::vector<uint8_t> kid;
-      RCHECK(reader->ReadVec(&kid, 16));
-      key_ids.push_back(kid);
-    }
-  }
-
-  uint32_t data_size;
-  RCHECK(reader->Read4(&data_size));
-  RCHECK(reader->ReadVec(&data, data_size));
-  return true;
-}
-
 SampleAuxiliaryInformationOffset::SampleAuxiliaryInformationOffset() {}
 SampleAuxiliaryInformationOffset::~SampleAuxiliaryInformationOffset() {}
 FourCC SampleAuxiliaryInformationOffset::BoxType() const { return FOURCC_SAIO; }
diff --git a/media/formats/mp4/box_definitions.h b/media/formats/mp4/box_definitions.h
index 2dfab63..026effe 100644
--- a/media/formats/mp4/box_definitions.h
+++ b/media/formats/mp4/box_definitions.h
@@ -44,21 +44,11 @@ struct MEDIA_EXPORT FileType : Box {
   uint32 minor_version;
 };
 
-// If only copying the 'pssh' boxes, use ProtectionSystemSpecificHeader.
-// If access to the individual fields is needed, use
-// FullProtectionSystemSpecificHeader.
 struct MEDIA_EXPORT ProtectionSystemSpecificHeader : Box {
   DECLARE_BOX_METHODS(ProtectionSystemSpecificHeader);
 
-  std::vector<uint8> raw_box;
-};
-
-struct MEDIA_EXPORT FullProtectionSystemSpecificHeader : Box {
-  DECLARE_BOX_METHODS(FullProtectionSystemSpecificHeader);
-
   std::vector<uint8> system_id;
-  std::vector<std::vector<uint8>> key_ids;
-  std::vector<uint8> data;
+  std::vector<uint8> raw_box;
 };
 
 struct MEDIA_EXPORT SampleAuxiliaryInformationOffset : Box {
diff --git a/media/formats/mp4/box_reader.cc b/media/formats/mp4/box_reader.cc
index 4368d8d..5105726 100644
--- a/media/formats/mp4/box_reader.cc
+++ b/media/formats/mp4/box_reader.cc
@@ -75,17 +75,15 @@ bool BufferReader::Read4sInto8s(int64* v) {
   return true;
 }
 
-BoxReader::BoxReader(const uint8* buf,
-                     const int size,
-                     const LogCB& log_cb,
-                     bool is_EOS)
+
+BoxReader::BoxReader(const uint8* buf, const int size,
+                     const LogCB& log_cb)
     : BufferReader(buf, size),
       log_cb_(log_cb),
       type_(FOURCC_NULL),
       version_(0),
       flags_(0),
-      scanned_(false),
-      is_EOS_(is_EOS) {
+      scanned_(false) {
 }
 
 BoxReader::~BoxReader() {
@@ -102,8 +100,7 @@ BoxReader* BoxReader::ReadTopLevelBox(const uint8* buf,
                                       const int buf_size,
                                       const LogCB& log_cb,
                                       bool* err) {
-  scoped_ptr<BoxReader> reader(
-      new BoxReader(buf, buf_size, log_cb, false));
+  scoped_ptr<BoxReader> reader(new BoxReader(buf, buf_size, log_cb));
   if (!reader->ReadHeader(err))
     return NULL;
 
@@ -125,7 +122,7 @@ bool BoxReader::StartTopLevelBox(const uint8* buf,
                                  FourCC* type,
                                  int* box_size,
                                  bool* err) {
-  BoxReader reader(buf, buf_size, log_cb, false);
+  BoxReader reader(buf, buf_size, log_cb);
   if (!reader.ReadHeader(err)) return false;
   if (!IsValidTopLevelBox(reader.type(), log_cb)) {
     *err = true;
@@ -137,12 +134,6 @@ bool BoxReader::StartTopLevelBox(const uint8* buf,
 }
 
 // static
-BoxReader* BoxReader::ReadConcatentatedBoxes(const uint8* buf,
-                                             const int buf_size) {
-  return new BoxReader(buf, buf_size, LogCB(), true);
-}
-
-// static
 bool BoxReader::IsValidTopLevelBox(const FourCC& type,
                                    const LogCB& log_cb) {
   switch (type) {
@@ -178,7 +169,7 @@ bool BoxReader::ScanChildren() {
 
   bool err = false;
   while (pos() < size()) {
-    BoxReader child(&buf_[pos_], size_ - pos_, log_cb_, is_EOS_);
+    BoxReader child(&buf_[pos_], size_ - pos_, log_cb_);
     if (!child.ReadHeader(&err)) break;
 
     children_.insert(std::pair<FourCC, BoxReader>(child.type(), child));
@@ -224,30 +215,16 @@ bool BoxReader::ReadHeader(bool* err) {
   uint64 size = 0;
   *err = false;
 
-  if (!HasBytes(8)) {
-    // If EOS is known, then this is an error. If not, additional data may be
-    // appended later, so this is a soft error.
-    *err = is_EOS_;
-    return false;
-  }
+  if (!HasBytes(8)) return false;
   CHECK(Read4Into8(&size) && ReadFourCC(&type_));
 
   if (size == 0) {
-    if (is_EOS_) {
-      // All the data bytes are expected to be provided.
-      size = size_;
-    } else {
-      MEDIA_LOG(DEBUG, log_cb_)
-          << "ISO BMFF boxes that run to EOS are not supported";
-      *err = true;
-      return false;
-    }
+    MEDIA_LOG(DEBUG, log_cb_) << "Media Source Extensions do not support ISO "
+                                 "BMFF boxes that run to EOS";
+    *err = true;
+    return false;
   } else if (size == 1) {
-    if (!HasBytes(8)) {
-      // If EOS is known, then this is an error. If not, it's a soft error.
-      *err = is_EOS_;
-      return false;
-    }
+    if (!HasBytes(8)) return false;
     CHECK(Read8(&size));
   }
 
@@ -259,13 +236,6 @@ bool BoxReader::ReadHeader(bool* err) {
     return false;
   }
 
-  // Make sure the buffer contains at least the expected number of bytes.
-  // Since the data may be appended in pieces, this can only be checked if EOS.
-  if (is_EOS_ && size > static_cast<uint64>(size_)) {
-    *err = true;
-    return false;
-  }
-
   // Note that the pos_ head has advanced to the byte immediately after the
   // header, which is where we want it.
   size_ = size;
diff --git a/media/formats/mp4/box_reader.h b/media/formats/mp4/box_reader.h
index 92e85fc..6b59361 100644
--- a/media/formats/mp4/box_reader.h
+++ b/media/formats/mp4/box_reader.h
@@ -101,14 +101,6 @@ class MEDIA_EXPORT BoxReader : public BufferReader {
                                int* box_size,
                                bool* err) WARN_UNUSED_RESULT;
 
-  // Create a BoxReader from a buffer. |buf| must be the complete buffer, as
-  // errors are returned when sufficient data is not available. |buf| can start
-  // with any type of box -- it does not have to be IsValidTopLevelBox().
-  //
-  // |buf| is retained but not owned, and must outlive the BoxReader instance.
-  static BoxReader* ReadConcatentatedBoxes(const uint8* buf,
-                                           const int buf_size);
-
   // Returns true if |type| is recognized to be a top-level box, false
   // otherwise. This returns true for some boxes which we do not parse.
   // Helpful in debugging misaligned appends.
@@ -156,9 +148,7 @@ class MEDIA_EXPORT BoxReader : public BufferReader {
   const LogCB& log_cb() const { return log_cb_; }
 
  private:
-  // Create a BoxReader from |buf|. |is_EOS| should be true if |buf| is
-  // complete stream (i.e. no additional data is expected to be appended).
-  BoxReader(const uint8* buf, const int size, const LogCB& log_cb, bool is_EOS);
+  BoxReader(const uint8* buf, const int size, const LogCB& log_cb);
 
   // Must be called immediately after init. If the return is false, this
   // indicates that the box header and its contents were not available in the
@@ -180,9 +170,6 @@ class MEDIA_EXPORT BoxReader : public BufferReader {
   // valid if scanned_ is true.
   ChildMap children_;
   bool scanned_;
-
-  // True if the buffer provided to the reader is the complete stream.
-  const bool is_EOS_;
 };
 
 // Template definitions
@@ -220,8 +207,8 @@ bool BoxReader::ReadAllChildren(std::vector<T>* children) {
   scanned_ = true;
 
   bool err = false;
-  while (pos_ < size_) {
-    BoxReader child_reader(&buf_[pos_], size_ - pos_, log_cb_, is_EOS_);
+  while (pos() < size()) {
+    BoxReader child_reader(&buf_[pos_], size_ - pos_, log_cb_);
     if (!child_reader.ReadHeader(&err)) break;
     T child;
     RCHECK(child.Parse(&child_reader));